Science Fiction Press has posted a call for submissions of sci-fi short stories of 2000 to 5000 words. This is a new market set to launch in March. They will be publishing quarterly ebooks and paperback editions. Payment is a $50 advance against royalties. You can find all the details here
A big thank you to Katherine Tomlinson for the link!!
UPDATE: Ralan.com declared this a dead market on May 2, 2013.