Personally I would not ride the trampa deck without bindings. And if you’re getting bindings, then you could just top mount everything in a box in the middle like Ben did:
But if you’re not doing serious offroading, then a bottom-mounted enclosure would definitely look cooler.
A 16s4p would fit nicely in any enclosure meant for 12s4p + ESC, like Big Ben’s Haero Bro enclosure, if you top mount the ESC (you could 3d print Poast’s enclosure for the 100D, or get one from Apex if you have the money). That’s what I was going to do before I sold you the 100D 
Since you need 6384 motors, you could get those from Apex and then save on shipping by also ordering the deck from them 
Only 190kv in stock atm though