The fact of the matter is, there's only so many ways to throw a punch.
When I trained in Hung Ga, guess what I was taught? How to throw a punch with a strong base using your your legs, your hips, your shoulders, and putting your whole body behind the strike.
When I trained in Sanshou, guess what I was taught? How to throw a punch with a strong base using your your legs, your hips, your shoulders, and putting your whole body behind the strike.
When I trained boxing, guess what I was taught? How to throw a punch with a strong base using your your legs, your hips, your shoulders, and putting your whole body behind the strike.
When I trained Muay Thai, guess what I was taught? How to throw a punch with a strong base using your your legs, your hips, your shoulders, and putting your whole body behind the strike.
People who want to see "Kung Fu" are trying to find some guy who uses some showy flowery high kick flying bullcrap in a fight. There's some places that do that, and train that, but they aren't fighting schools so much as a opera houses and WuShu schools.
A guy using a Chinese Martial Art to fight will use techniques that are meant for fighting, for example a jab, a cross, hook, uppercut, overhand, roundhouse kick, straight kick, side kick, etc. (but with their chinese names).
As was said, there's so many styles and facets within Kung Fu. Some instructors choose to favor certain ranges and certain techniques more than others. But when it comes down to it, the ones that will work in a sport fight or an MMA fight will be the same basic punches, kicks, throws, and sweeps that you already see in combat sports.
At the same time, people have to understand, that most Kung Fu schools teach whatever style they teach not just as for fighting. Many of the arts and schools teach it as a way of life. They make it into an all encompassing life system, including health practices, chi kung, forms, meditation, ethics, self-defense (dirty fighting, I learned a lot of eye jabs, groin strikes, and throat punches in Hung Ga), weapons, etc.
So it's not quite the same as going to a Muay Thai gym and just training Muay Thai all day everyday for the purpose of getting in the ring and fighting. Some Kung Fu schools don't even incorporate combat sports into their curriculum, likewise they wouldn't do well in a sport fight format. In a way, some Kung Fu schools are almost like joining a cult (for lack of a better term). You're being introduced to a way of life. Likewise, some schools will also favor certain aspects of the system more than others (some places really into street fighting and self-defense; most of that stuff can't be used for sport, some places will favor sport fighting and Sanshou/Sanda, some places internal health and chi kung, etc.)
Most Muay Thai gyms focus on sport fighting in the ring, many BJJ places focus on sport fighting with the gi, some places focus on sport fighting without the gi, etc.
If you take a Kung Fu guy who practices the whole system as a way of life, and goes to the Kwoon somedays practicing sport techniques, some days meditation, some days weapons, some days forms, etc. and put him up against a Muay thai fighter who goes to the gym everyday and just trains for a Muay Thai fight, who do you think would win in a sport fight???? The Muay Thai guy of course, that's all he does everyday.
So with that understanding, if you put an MMA fighter against a Kung Fu guy in an MMA fight, the MMA fighter will win of course.
The fact of the matter is, if a Kung Fu guy were to fight in MMA he would have to train for MMA. If he's going up against a professional MMA fighter who trains for that type of combat 9-5 6 or 7 days a week, the Kung FU guy will have to train for MMA 9-5, 6 or 7 days a week. All of this has been proven already.
I think good points were already brought up. Machida trained for sport and brought his Karate into the sport realm. He cross trained and focused on MMA and that's why he's successful. Karate was his base style but he is a Mixed Martial Artist. Same way GSP, came from a Karate base, but he is a mixed martial artist.
The fact that Muay Thai, Boxing, BJJ, and wrestling are so prevalent and work so well is because they are very sport oriented. If you go to a boxing gym all they are working on all day is geared toward sport fighting and competition.
A Kung Fu guy fighting in a sport format will most likely look pretty similar to a Muay Thai guy, a wrestler, judoka, or a boxer, that's why there's Sanda and Sanshou as a sport form for Kung Fu. The most effective techniques from Kung Fu, are going to be punches, kicks, throws, and takedowns. Not much different than any other fighting art. The difference is in the training methods. I completely agree, some stuff in Kung Fu seems completely useless in a fight, but not all Kung FU is about fighting.
Here's some more examples of what Kung Fu toward sport fighting will look like:
YouTube - New York Hung Ga San Da kickboxing sparring demo (2009)
YouTube - NYHG San Da Drills (2010)
Basically looks alot like boxing, Muay Thai, Sanda, etc. right? Because those are the techniques from Kung Fu that work best in combat sports and in general fighting.
I'm not sure exactly what you guys are looking for. But if you want some dude to walk to the octagon dressed in some traditional chinese Enter the Dragon looking outfit and do flashy kicks flowery kicks (Cung Le already does that minus the ridiculous wardrobe) chain punches, tiger claw (which would be considered illegal in MMA), and for Joe Rogan to boast about how said fighter has been living in a Shaolin Temple since he was a orphaned as a 2 year old and training in Kung Fu with monks for 25 years; I seriously doubt this is ever going to happen. Either that, or you are just as deluded as the silly Karate guys spliced in that Joe Rogan YouTube video above.
Sanshou and Sanda fighters are the best bet for seeing a Kung Fu guy in MMA, simply because they train the way fighters do geared toward sport and ring techniques and actually applying the techniques in live fighting and not also spending time doing forms, meditating, doing chi kung, and self-defense dirty fighting stuff. It's focused on sport and sport oriented techniques. Traditional Kung Fu often doesn't train the same way, because most of the styles are all encompassing systems.