Can you post the AHs of the kits an the dimensions?
Such boxes seems to be very good for mobile using if they fit the available room.
Look here:
http://elweb.info/dokuwiki/lib/exe/detail.php?id=cityel_akkukorb&media=cityel:motorraum.jpg We have this little electric cars here
elweb.info
and have a lot of do-it-yourself conversions to LiFePo with single cells. It would be nice to have boxes that fits to the room with the cells in it... mechanical hardened and with access for ech cell for the BMS.
I use 12V Blocks, but there i have three BMS and cannot access the single Cells... And three 12V Blocks are only 12 Cells, not 15 or 16 whats better...
Maybe you can make a three block design with 5 cells each that fits the available room the three PB-blocks use in the linked picture above? Keep in mind the middle place is the smallest (350x160x210 mm), what fits there will fit at both sides too.
Greetings,
Werner