Seems like the LiFePO4 CALB re a little lighter, though possibly bulkier. A pack of 4 with nominal voltage 12.8 is two pounds lighter but significantly larger, I think. So the LIFeMnPO4 would get the same energy storage into a smaller area, with signficantly more weight, though nothing extreme. Here are the deets on the cell you mention that I used for comparison:
CA100FI 100Ah CALB EV, Li-Ion, Lithium, LiFePO4, LiPo, Prismatic Cell Battery
Seems the LIFeMnPO4 at 12 four-packs for 144v would fit--on paper--a space roughly 25" wide by 22" deep and 9" tall.
Not a lotof range in 14.4 kwh but my vision is a fully parallel system to work completely independent of an ICE. It would be used in situations where the ICE is not ideal, not all the time.
Looks like building it would cost like $20k!
Yikes.