No, I don't think he's mentioned more than once. Aemon mentions him during some semi coherent babbling, I THINK.
I thought the 3 Hedge Knight books were great, though I'm a total ASOIAF history nerd. It has a bunch of Targaryens in it and refers heavily to the Blackfyre rebellion.
A brief history of the rebellion is that the 4th king Aegon was a total manwhore (much moreso even than Robert) and ended up legitimizing all of his bastards on his deathbed. One of those bastards was Daemon, who was born illegitimately to two Targaryens. He was a badass but obviously with the phrase "Blackfyre pretenders" being thrown around in ASOIAF, it's not a spoiler to divulge that his rebellion failed.
The Hedge Knight series has a few spoilers. One of the spoilers I found out before I started reading them. In fact, it was the reason I started.
If you wanna know what the spoiler is, I'll pm it to ya. That series might reinvigorate your interest in the main books like it did for me.