I've developed a relationship with a dozen or so freelance designers. Most of them are quite happy to slice a PSD layout into (X)HTML conforming to the standard of my choice. Most also happily convert it into a Wordpress, Drupal , Joomla , etc theme with very little turn-around time.
I'd head to odesk, freelancer.com, etc and put a few projects out for bid. This gets you a roster of talent that you can pick from, whoever happens to be on-line at the time gets the job.
The usual price I pay just for slicing is $15 - $20, and it takes about an hour. Converting to themes goes from $75 - $200, depending on the complexity of the design. Its worth it to me to just pay someone to do what anyone could do, leaving me more time to spend on tasks that only I can do (like getting fresh content out daily, hunting for quality backlinks, etc ..)