Here is another way to go about this:

Look on eBay for the "VeriFone VX510" credit card machine.  This machine is obsolete and consistently under 50 bucks used, and it can download software at least three ways: 1) RS232 through a win32 command-line loader 2) through its dialup modem (same protocol as RS232 loader) 3) it can copy the programming from another terminal using a crossover serial cable. 

I can compile for this platform, and it also has a printer so it can spit out e.g. paper wallets and transaction logs.  I have already demonstrated the printer can print QR codes.

These things have tiny amounts of memory... if someone had written the verification code in C where its dependencies were minimal (e.g. relevant crypto code clipped out of openssl so it didn't depend on any external libs, and of course it can and should talk to a serial port) I could easily compile for this thing.