I misread - thought you already had vehicles. Try this one from the Wayback Machine. I only downloaded one model so I don't know how many of the links work - found via a quick Google search for: Russian tank model 3d. I'm pretty sure there's more out there.

http://web.archive.org/web/*/http://military3d.boom.ru/

Note these are in Lightwave format. You can use PoseRay to convert to .obj if needed. Select all the parts at once and they should come in as one model.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken