There are a few paper-based analogs. I seem to remember reading of a handful of towns that created there own voucher (currency) that could be used in all the shops in that town.  Maybe Ithaca NY (Cornell) was one?

Yes agree, the US markets are highly regulated and the FATF is driving KYC rules thru the entire global payments systems via SWIFT. Remember that anyone using the VISA or MC networks must have a BIN to even apply for access. 

I think your system will work and if you work 100% in BTC you may not even need a money transmittal license until such time BTCs are formally defined. Having said that, there is a elephant in the room that simply cannot be ignored. For everyday mom and pop shops, they would really have to be BTC enthusiasts b/c at present the # of potential customers, likely sales and the costs and risks of running a separate offline payments system that has to be marked to market and cashed out on an exchange is likely to be a very hard sell given the dollar amount in tax savings. 

Or to put it another way, can you think of actual products or specific types of stores that would benefit from adding a BTC capability and have you constructed a simple spreadsheet showing the # of such goods or services they would have to sell to break even on their startup costs (meaning lower cost per transaction + interest on deferred taxes)?

As some point all of us early adopters and innovators will need to level up quite a bit in terms of infrastructure/support (hardware+ software, txt & video manuals = ease of use) if we expect to see the growth in BTCs acceptance and usage that gets us to some sort of tipping point in the brick & mortar world. Strategically, I am developing a pretty clear vision of how BTCs can interact with the current global payment systems, and to me that's exciting. As for network and app development, I am a total noob, all I can offer is a list of must have functionality.