First, throw away the printed Tower catalog and go to the web site. The catalog shows only what the marketing department likes. In addition to Tower, here are a few kit sources. Others will add more.
http://www.sigmfg.com
http://www.balsausa.com
http://www.btemodels.com
http://www.hobby-lobby.com/rcglowpr.htm
http://www.proctor-enterprises.com
http://www.radicalrc.com
http://houseofbalsa.com
Some of these sites have a lot of kits and others only have a few.