So I waited again, nothing came of it. I asked him again in February, around Valentine's Day. He said he'd do it over the weekend, and asked me to resend my character info (which I did).
Well, it's April, and I'm still waiting. Meanwhile, this person keeps making new art, coloring art for others, and doing collaborations with other people. Oh and he's now asking people for money for an art raffle to get money to go to Otakon. The winner gets some art or something.
If by now, you know who it is, please don't mention his name. The person is well known in certain areas of the fandom and has some rabid followers (not to mention, I got in trouble with one of his best friends, so I want to prevent drama by saying his name outloud). I did a search to make sure this person hasn't been mentioned before - and he hasn't. But I'm not the only person he promised stuff to, and considering all this activity of his... I want to contact him but I'm really pissed off by now and don't trust myself to keep my cool.
Followup as of 04/19 - I sent a DA note to the artist and he replied a few minutes later, refunding the money with interest and apologizing a lot for his delay. He still intends to finish the image. Thanks for your advice. :)