Ryan Bader.... He's pretty much an afterthought at this point, but his resume is phenomenal. Besides that one bad loss to Tito, he's only lost to Bones, Rumble, Machida, and Glover. Meanwhile, he's defeated Little Nog (2x), Rampage, Cavalcante with one hand, Rashad, Phil Davis (2x), Latifi, King Mo, Vassell, and Jardine. After the big 3 (Bones, DC, Rumble), you can make the case that Bader has been the next best LHW over the last decade.
Matt Serra.... Most people scoff and dismiss him as a fluke, but he had a very stellar career. Marred by close losses (caught by Shonie with seconds remaining when he was about to win a decision, a great fight against BJ in '02, and a close SD loss to Din Thomas), Serra was always a threat and was only finished once. Heavy hands and a great ground game. A very solid overall fighter.
Sean Sherk.... Doesn't receive enough recognition as one of the best LWs ever. He split time at WW and still compiled a 36-4 record and only ever lost to the absolute best of the best (Hughes, BJ, GSP, and Frankie). He dominated Florian to win the LW title. The dude was 5'6 and may have had shorter arms than Artem and he still wrecked most of his opponents.