Brett Henderson recently released his Saab 340, featuring a fully modeled passenger interior. More information available from Flight Simulations and Designs website.
http://www.simviation.com/fsnd/Downloads.htm (alternate download http://www.simviation.com/simviation/download.php?ID=3301)
02may2010 update: Sorry guys… the FSND website is no longer available. I provided an alternate download link to Simviation so you can continue to enjoy Brett’s awesome model! Cheers!