hi kent-man,
I know what you mean about the fun part or RC being the modding and building i ust have made about 20 aircraft but never really liked flying them,LOL,
but dont be put off modding because you dont ave the tools, i do all my building in an 8 foot by 6 foot shed and the only tools i have are a pillar drill and hand tools.
got some pictures of the the mattracks design ,looks complicated to try and copy but i found the 4,us design just went in the shed and started building it out of brass, i reckon with a simple bit of braising and some tank parts it would be easy and fun to build.