Why are you thinking border? A shade garden doesn't need a border. If you feel you need a border, what about Cimicifuga racemosa? I am using it along one portion of my deer fence.

I have Sambucus nigra variegata growing in almost full shade (a touch of morning sun) and it does very well and is a real highlight in the darkness. Can be trained and pruned to grow in any shape you want; mine has been kept pretty tall and narrow. Might overwhelm the shade bed in time if not kept in check.

There is an older thread somewhere asking about shrub for deep shade, maybe on shrubs forum? Lots of suggestions there.

I definately need a tall border...this garden is about 60' long and runs the length of a portion of the back yard. Behind the garden is a section of trees and then the road. I want to block out as much of the road as possible.

Sounds like you might want evergreens then? The tall grasses you were thinking at the outset might indeed work too. How much depth do you have? You could make a boffo row of rhodos, or a yew hedge, or a variety depending on what impression you want. At that length it sounds like less a border behind the shade garden than a feature/screen in itself.

What about a screen of hemlocks or large rhododendrons? Something more evergreen if you are looking to screen a view. As for tall perennials, I like goatsbeard. Mine gets bigger each year and now tops five feet. It is also sturdy. If you try grasses in shade, the narrower leafed types will stand up better. Two that I have used with success in part shade are Miscanthus sinensis 'gracillimus' and M. sinensis 'Morning Light'. The wider the leaf, the more they flop in shade. Deb

yews
kerria japonica
japanese holly
Eleutherococcus sieboldianus 'Variegatus'
pieris
fothergilla
kalmia
mahonia

Lots of things to choose from.