HP Tuners should be making this happen. Even if the checksum tool is separate to the VCM software and 'leaked' via a forum.
The can bridge is a nice idea too, much easier for the home enthusiast to create than going down the checksum tool road. I predict there will be solutions available shortly. There is definitely a market for it. If someone put together a can bridge that is rock solid bug free and covers many vehicles I don't think a charge of say $200 per unit is ridiculous. Good profit margin once dev costs are recovered.