I met up with so-and-so Darkwalk in the thieves' guild, and we arranged to meet at the splurging sturgeon, (using only a thief) and then to go find some people's house, yada yada. WELL, i've been all over that map and Darkwalk is nowhere to be found. do i need to come at night? do i need to hide the rest of my party in the blushing mermaid? what's up?

yep go at night and he will be there.

Don't worry - I could never make him appear either

I have just done both of the quests for him.

He says meet him at Dusk, which is about hour 20, at this time I would stay away from visual sight of where he will stand, and go back to check once in a while until the AI placed him there.

I also made sure I went on the evening of the day each quest was given, afterall, you don't arrange to meet a mate in a pub on Tuesday and arrive on the Wednesday!! :)

Toby