I have the design of mine but I used the motors for my ant arena effects, need to get some more.

I'm also not sure if I can get my design in the weight:

1mm Ti base plate
1mm Carbon fibre top
1.2mm Ti front
10mm HDPE bulkheads (held in with Ali angle)
1 x 1300mAh 11.1v battery
1 x sabretooth 5A
2x MFA 100:1 motors
1 x 12T gear and 1 x 24T gear (possibly, may be less)

And the clincher
1 x speedo 900 replica for my weapon