While I agree the Cheap SDR is a wonderful thing when accompanied with the setup Scott described, it's in no way a substitute for a BCDx36HP, IMHO, with exception to the DMR decoding while using DSD+. I love the display in SDR# and HDSDR. The ability to look at the radio spectrum, and the decode possibilities are endless, but there is no real replacement in the HP-1 Extreme and or the x36HP in the price category for monitoring abilities, for trunked and conventional P25 (OR Phase 2). I highly recommend to anyone interested in the cheap SDR to check it out. It's cheap, fun, and a great tool for monitoring. It's just not the answer for all monitoring possibilities, just another tool in the box.Indeed. And...for those of us that like to play with this stuff today, we already have, in my opinion anyway, a scanner that blows away Uniden's offerings. Two RTL dongles, UniTrunker, VBAudio Cable or Virtual Audio Cable, and DSD construct a scanning system with multi-tiered prioritization, visual display of the entire system in operation, and digital decoding. Sure it takes a little work and patience to cobble it all together. And OK...it doesn't scan conventional frequencies. But add a 3rd dongle and SDR# and you're in business. So now we're up to a whopping $60 or so. Yikes, the possibilities.
The majority of folks won't want to cobble the above together because it's not their niche. Wouldn't it be great to see a Kickstarter for a scanner project as you suggest. That would be a kick in the pants for the major players. I have to wonder if those that have the wherewithal to produce such things as HackRF, bladeRF, Airspy, etc., would even consider doing so for something as "mundane" as a scanner. I think instead they would suggest to you (the end user of their product) to "roll your own" as we already have thanks to the above listed components.
The bottom line in my book is that those RTL dongles have changed the world with regards to the radio hobby at VHF and higher, and they are the catalyst for many more robust things to come. Whether scanners are numbered among those things? Only time will tell.