Actually, it looks like an interesting project with an extremely very good profit margin!
Unlikely that a USRP unit could be a $100 item as originally suggested. Cost could be minimized if the board was simply cloned, sold with exchangeable or multi-tuner expansion and without technical support.
A major issue for distribution would be that it would be highly improbable to obtain Part 15 FCC approval for transmission for a wide spectrum device. Would the technology still be of interest if it were developed as a receive only project?
If your going to repeat what they have done, the price alone will be too high.
If you can find someone to do a mass produced ASIC, then I suspect a $100 device might be possible.
The Transceivers are not a problem, as you can S/W disable them, and also S/W control just what bands they operate in. In effect, the S/W you release with the parts would have to comply with the FCC regs .
Also, there is the WhiteFi standards coming out that are wide band friendly.
The key to this is ASICs... or at least mass produced ones. Once you get this under $100, these things replace AM/FM radios, TVs, WiFi routers, CBs, FRS, police radios, cell phones... you get the idea.
The key will be to release S/W control code. Thats where you obtain FCC licensing.
Or at least as I see it...