I have the partslist and a printout of the main PCB up on the build section for you DIYers.
And, I have finally nailed down a cost. For the custom parts of the RN-9090 (main PCB, button pad PCBs, Teensy and Atmega328s with custom code) I have settled on a cost of $180. In addition, I estimate the common components to be ~$300 for a single unit (~$500 total) not including a power supply or enclosure. However, if parts were purchased in bulk, that price could come down to ~$225 per unit for the common parts not including power supply or enclosure. I will be sending an e-mail out to people who have e-mailed me in the past and see if we can get some people interested in doing some beta testing. If you have good soldering and construction skills and want to be a beta tester, send me an email through the contact page.