My biggest mesh was about 700T, and I had no problems, but very strong slowdowns! I still use Blender 2.49b on windows xp and a quite old system, Pentium 4, 1Gb RAM, Ati X300.
Did you save former versions? Then you could test which one still imports.
I didn't use the paint tool and imported it into Blender jet.

Nice results so far.

In case you need to correct proportions now or later, I found the grab tool very handy to adjust the overall shape.