Quick update, I went with the Triumph 20-30 Liter tank bag (part # A9518032) and it works great. It holds plenty of stuff and of course it comes with the Triumph Cool Factor.
I have the SW-MOTECH style bag and connector on my Sprint ST, and I love it. http://www.twistedthrottle.com/brand/sw-motech-bags-connection?limit=144&product_type=479 has a bunch of fittings that one could modify just about any bag with. I am going to "modify" the ST bag so it will fit on my R3C. It would appear to be a simple mod, just drilling out four new holes under the tank bag and refitting the attachment.