http://forums.sketchucation.com/viewtopic.php?f=81&t=35657 is a tutorial for a leather Barcelona Chair...
http://forums.sketchucation.com/viewtopic.php?f=18&t=14073&p=105815&hilit=sofa#p105815 has links for modeling a sofa...
Look in the 'Tutorials' forum there are several threads that might be of interest to you - you can 'Search' within a forum [left-side search] or the whole SCF site [top-right search]...