Hm. Isn't the problem that the engine can't render more pixels than the screen's wide/high?

So on a 1280*1024 screen, I can't have a 3000*3000 window, can I?

You can try rendering to a bmap, though I've never done it (try muffel's method first). If his method doesn't work, I think I'd start with looking at view.bmap in the manual. You may need "bmap_zbuffer"...