Hi,
I have some C1 bits on ebay UK atm. (05/09/2015) - Hashboards, Beagleboard and cable kit.
I like the C1 - i have 1 running 24/7 on stock parts - I wonder what the total sales were for the C1's - couldn't have been more than a few thousand units.
We will never know. But I suspect it was a decent amount, no S3 launch. But a lot of people wanted to try the water cooling (including myself).
Only way would be if someone went back and traced payments and made an estimate, but I don't see this happening.