No Miscanthus will be invasive in your zone. You'll be lucky to get it to bloom, much less to self-sow.

I'd try Miscanthus sinensis 'New Hybrids,' 'Early Hybrids' or 'Late Hybrids.' They are reliable germinators, and generally available seeds.

There are probably no popular named Miscanthus which will grow true from seed in your zone.

I'm also curious about this as I'd like to grow some in Minnesota. What do you mean by growing true? Would it not be a good idea to start them outside from seed? Would starting them inside from seed work better?

Nick -- here's a page at the University of Minnesota about M. sinensis:

http://miscanthus.cfans.umn.edu/default.htm

If you click on the "Recommendations for use" they recommend that gardeners do NOT plant it from seed since these plants could self-seed and invade wild areas:

http://miscanthus.cfans.umn.edu/recommendations.htm

Yea I saw that, it's funny though because it's actually planted in some city parks around the city. As well as along the roads and highways here.

Well it's true, M. sinensis is everywhere. I think for the most part
when you see it in parking lots, etc. that they've used vegetatively
propagated cultivars. One I see all the time (and that was in my yard
when I bought it) is M. sinensis 'Gracillimus'. This year I'm pulling the last of it out.