The elcon looks like a cost effective unit for known battery types. But the default cell count and voltages do not look suitable for your special chemistry batteries (LiMn2O4), so you will need to have it reprogrammed, or order direct with a suitable charge profile. I haven't seen evidence of diy programming on those units.
Edit, maybe I stand corrected: $355 and LiMn2O4 is an option at 72v
http://www.electriccarpartscompany.c...lay_p_349.html