Last year at Otakon (2004) myself and my boyfriend commissioned two pictures from http://mazokugirl.deviantart.com/. She said she'd get them done within a couple weeks of the con. She was very nice, and I talked to her for a bit.
After months of emails sent with no replies, my boyfriend got ahold of her on MSN, and spoke to her briefly, and she promised they were ready, she was sending us preliminary sketches, would have the finished ones to us by next weekend, and that she'd gotten the emails, just hadn't gotten around to replying to them (for four months..?). Cue another 3 months of waiting. We sent another email, which got ignored, and after that, we've just about given up.
Both these commissions were paid for in full, and was also the first and only time I've ever commissioned anyone, so this has left an incredibly sour taste in my mouth. I would've been satisfied with even the preliminary sketches she promised, but no.