We have similar transmitters available as kits. $110 for a 1 to 1.5 watt transmitter and $135 for a 10 watt version. Circuiit board size is 4 x 5 inches. All PLL frequency control. Also, higher power amplifiers available as well. http://www.freeradio.org
Hmm, how about posting a DIY build as well? I know you’d like to make a little money out of it, but I’m sure it would be appreciated. Once people see how hard it is to make, I bet they’ll buy it from you anyway!