I think you have some wonderful ideas to front this grass. Gaillardia would look great. The yellow and red flowers would pop off the blue foliage. Also, maybe a coreopsis. A pink blooming, red-foliaged canna would be a really stunning contrast with the foliage and a compliment to the Dallas Blues seedheads which can be very pinkish-purple.

Thanks for your response Grass guy. If I do the coreopsis I think I will go with Zagreb for the foliage contrast. The canna suggestion was great also.

I like Rudbeckia of any sort, Echinacea and Joe Pye weed, daylilies too.

Here is a link that might be useful: More about growing switchgrass, pics too