The only type of Lithium "kits" that I know of are the ones for converting Prius's into plug-in hybrids. Those have a rather limited electric only range, and are still very expensive.
The only guy that I know with an electric car using lithium, when asked about the cost of the batteries, said "about that of a new car".
I think it would make sense to drive an electric car right now with lead batteries. When the price of exotic batteries comes down, upgrade to something fancier.
Also, I believe the Solectrias can run on a range of voltage, with 144V being near the lower end. I had hear that they can sometime have trouble as the pack discharges, it hits the low voltage cut-off point of the controller. For example, if you try accelerating up a big hill with a low battery, your power could cut out completely. I had that as an issue for a while with the DC/DC converter on my motorcycle. An extra battery solves the issue as it brings you voltage up another 12v.
I think most of the Solectrias ran 156V (13 x 12v batts) so that it wasn't a problem
There is a guy in Georgia who has a collection of 3 Solectrias, each with different batteries, but it looks like he must have recently sold the Lithium one.
Stephen Taylor's Solectria Forces
Stephen Taylor's 1999 Solectria Force
Abel Saucedo's 1997 Valence Lithium Solectria F
The third link above (Green Stripe) is the lithium car. The batteries are marked as "engineering samples", so possibly the original owner got the batteries somehow through his work or industry.
Stating how much money that was spent on a conversion is OPTIONAL on the EV Album, and it seems that it is often left off on exotic battery types.