Here's a link to three inexpensive ones that use Tripath chipsets. The downside is that the some of the components are surface mount type so shaky-handed and vision challenged kitbuilders might have a problem. Also, the power supply isn't included. The 100 watt @ 4 ohms Amp 1B at $63 plus shipping is especially interesting - quite a bit more veristile than the 15 watt Sonic Impact amp.