Less Than Three Press

Less Than Three Press bills itself as a romance press but accept submissions in all genres. Right now they're open to serial stories, and ebooks of 25,000 to 50,000 words. That's the sweet spot, but they'll accept as low as 10,000 words up to 200,000. Payment varies per project. http://www.lessthanthreepress.com/submissions.php

Of interest here is the anthology call for "Private Dicks Undercover". They're looking for shorts of 10,000 to 20,000 words with PI's willing to don any guise to break the case - and any genre will work. Payment is a flat rate of $200. Deadline is January 4, 2012. http://www.lessthanthreepress.com/anthology-submissions/