Try bamboo maybe, but install a barrier underground. The conditions you describe do not suit many other grasses. Chasmanthium latifolium (Northern Sea Oats) might work but really only gets 3 feet tall as far as I know. Perhaps one of the grass experts who ply this cyberspace will come up with better options for you.

Chasmanthium latifolium will grow close to the height you are seeking, and has a nice upright habit. It almost looks like a bamboo. Mine are planted on the west side of my house where they only get about 2-3 hours of direct sun each day, and they have thrived. Height is at least 3' tall by midsummer.

I have Calamagrostis brachytricha growing in quite a shady spot and it does well.

I have Miscanthus 'Morning Light' in morning sun only and it does just fine although doesn't bloom much. Your afternoon sun spot might be similar. The leaves are variegated so I don't care if it blooms. It does get 4' tall and is not an agressive spreader at all.

Thank you everyone! I'm not too crazy about the look of Northern sea oats, but I do like the other two suggestions. : )

Jen