I just got an email from Nancy at OSN Power. They have these cells for $2.50/pc if you buy 1,000 of them. They will also tab weld them for you for a nominal fee.
I also found a thread where someone has done some testing on them. Looks like they sag pretty bad above 20 amps. I would not consider these as a 50-amp cell as they are being touted. http://budgetlightforum.com/node/23887
Batteries, Chargers, and Battery Management Systems.