PJ- theres not much point in supporting the back, as theres no shock going through it, the 6 bolts on the front are only to stop the can falling of through vibration now really... as the shaft will be supported on both sides, all the force just goes into the bearings...having said that i might be putting an armour mounting plate in that kind of area anyhow so i might kill 2 birds with one stone just to stop the motor ever being able to fall apart even if all the bolts should fall out.

Alex- id probably go with the scorpion just because its a good motor out of the box.... and just because a motors an in runner... doesnt mean the spinup time will be pants... look at 720/galactus for examples of that.

If your going to the trouble of getting your bulkheads machined from alu like you showed me before- id suggest making your mounting for the motor the same as the one i made for 360 ages ago... so it supports the entire front cap of the motor, with its own bearing.