Well I just got done checking Ever Single G. I. Joe Vehicle toy ever made. could not find anything that looked like the Defensive Tank Alt Mode. I'll never make fun of Transformers repaints again, They use the same jeep (the V.A.M.P.) 26 times in 2 years with just new paint. Oh and burn I hope your not referring to the G1 Sparkstalker Transformer, Pink!?
I was thinking of doing a scratch build with some plastic molding tools I have.
So I'll be making Every part as a plastic cast piece, good thing I make Miniatures for a living.

*Edit; Okay I just looked up the G1 Stalker, it not a bad bot (other then the techno color explosion paint job). I'll give you that Burn, and thank for the tip.
But I still really want to know what the Defensive Tank is based on, so i can get a better Idea of what to make.