It used to be a truism that the science fiction genre was very well suited to the novella form. The arguments for this were pretty sound and logical: before the author could really let his or her plot unfold, thay needed to ground the reader in a world that was likely extremely different from the reader's own. This could take a bit of time, and could happen while the author was introducing characters and showing what each was capable of doing. Also, those Golden Age stories were (relatively speaking) much more idea-heavy than modern stories: they needed the extra exposition, because their readers did not yet know the SF ropes.
Although most of this still holds true (apart from the fact that "idea-heavy" seems to have fallen out of favor with some groups), the novella is one of the most difficult lengths to sell. Got a novel? If it's any good, it should find a home somewhere. Got a short story? Polished work will eventually sell. Novella? Hmm... tricky. There seem to be few places that want to deal with the form in any volume.
So I'm delighted to announce that my novella Branch has sold to
Wolfsinger Publications for publication as a stand-alone ebook in 2012 (note how stories of this length lose their quote marks and gain italics when they become stand-alone books). They have been a delight to work with so far, with quick response times and a contract that held no surprises - it contained precisely what the guidelines said it would. I look forward to working with their editorial team - and will be mailing off the contract as soon as possible.
Getting books accepted is always one of the highlights of my year.