The easy answer is no. There is no purple or red grass which will grow to 7-8' and be hardy in your zone.

The complication is that it is not likely 'Zebrinus' will hit that height in your zone either. Those heights are in perfect circumstances, which only happen in warmer zones.

Look at the red Panicum virgatums, like 'Shenandoah,' 'Rotstrahlbusch' and especially 'Squaw.' They'll get close to the same height as Zebra Grass.

Check out the Grass Comparison Chart, linked below, at Bluestem.ca. They specialize in grasses for cold climates, and have tons of useful information on their site.

Here is a link that might be useful: Bluestem Ornamental Grass Comparison Chart

I figured it was no....as far as Zebrinus height, all I can do is hope. Im in Cincinnati area and friends just south of Columbus has several Zebrinus (with 10+yr old root systems) and they hit 8 ft. I will mound plant mine for some "insurance" though

An awesome ornamental grass you might want to consider is 'Foxtrot' Fountain Grass. My Foxtrot were about 5 ft tall this fall with large/long red foxtail-like seedheads. Its a truely amazing grass.

The only down-side is that you would want to cut these back in the fall opposed to Panicam varieties that look exceptional dried in the winter.

Also, If you're considering Zebrinus then i would have to recommend 'Strictus,' which looks similar with the gold-bands, but has the tendency to grow less aggressively and not flop as much as the larger cousin Zebrinus.

It's not exactly a tall grass, but if your looking for something that is purplish, and would provide a border for cover.... I just saw this today in White Flower Farm's spring catalog. It's called Phyllostachys Nigra. Black Bamboo. Grows to 20-25 foot. Zones 6-9.

Actually, it is a grass...a member of the Poaceae family.