I hope sharing such finds is okay.
These Jeep modules from Batteryhookup.com may be a good option for conversions. If the DCDC converter could be hacked that would also be very useful as it's aircooled and I assume meant to power the Jeep's 12v bus. The battery module itself would need to be reworked but would yield 3.5kWh for $800
https://batteryhookup.com/products/jeep ... -12v-dc-dc