Therin lies the problem. Distribution channels for Lithium batteries are not established in the US. Sure there are dozens of people who will import them, but I'm not a big fan plopping down thousands of dollars for a product without support .
The only brands actually being sold in the US are from overseas based companies. The US based manufacturers won't even sell their batteries to a non-OEM manufacturer. Sure, they have a link on thier website to "tell us about your application", but what they really are looking for is someone ready to place a $500,000 order and wait a year for the product. I've exchanged emails with A123, Valence and EnerDel, just looking for more information, only to get the go-jump-in-a-lake reply. (In hindsite, I may have replied a little hastily to those emails.....)
The asian suppliers have thier issues too. ThunderSky doesn't have a decent BMS system, while LifeBatts are built-in and slick but very spendy. Interestingly enough, I have written to both and gotten prompt, informative replies.
So, I'm really stuck. Normally an EV conversion hinges on battery selection, and fitting the trays around them. What if my trays are more generic, allowing for multiple battery formats? It's easy to add spacers or mounting holes after the battery selection is made.
The key is still optimizing the use of space for batteries within the frame. So I still needed to grind a few thing off the lower frame rails. (For comparison, see the cardboard mockup, several posts back)