Does anyone remember who made the RB Lithium Battery from the forum

 

Are you referring to the ones made from cordless tool batteries?

 

There were several myself included that built battery packs from A123 cells
Tweety, for himself mostly
Jamie Dougherty for himself and was selling them for a very Short time
I built several packs for my own bikes.

No longer really worth the effort or cost as Li has gone mainstream and prices have come down.
If I had a non standard application...say location or power needs I'd still build one, but if its going in a battery box, not worth it.