I bought the upgrade kits for two lights and all the kit came with were the pucks, so I highly doubt someone would buy them for a DIY project. They'd have to match up the pins to each color, then build a controller, and put it in a case and find the right power supply. Seems like more trouble than it's worth.
I agree that the profit margin on two pucks would be high.
At this point you'd be better off buying a used G3. I had mine up for sale for $200 and had no buyers so I kept it as a back-up. IIRC the upgrade kits were about the same price.