I have been trying, on and off, to make a Tank Mark V in 1/72. When I saw Wayne McCullough's card model, years ago, I had the idea of printing it on to Tamiya's Pla-Paper and then somehow (with skills I don't possess) making it into a 'proper' model. But then 3D printing was invented, and my local library got a filament printer, and I found a free file on Thingiverse. I rescaled the file to 1/72 and had some success, but the file is a male and I want a composite (both; 'left handed' and 'right handed') so I have been trying to find a decent female sponson. I have met no success, so I took another look at Wayne's paper model and tried to use 3D Builder's mechanism for making 2D pictures into 3D objects; I tried this because I don't know how to actually make stuff in any 3D program; all I can do is adjust other people's creations. Here is my pathetic, laughable first attempt! If you know of any good quality females (ooh er missus) I would love to see them!
I think if you asked Wayne very nicely he may be able to turn his 3D Mark V sponson model into a .stl for you.
I know he has been creating .stl versions of his cardmodels - the 155mm Mle 1877 de Bange is the most recent example - downloadable from Thingiverse and Landships II.