Hey Sugarhill:
I have shade such as this. If you have a patch of drier shade, consider dicentra exemia simply because of it's very long mid-summer bloom. Mine just went out of bloom the other day. Behind a hosta with lighter leaves, I have a chelone "Hot Lips". This is one chelone that can withstand moisture or drought, and it has very dark green leaves, (so it looks good near a fern, or with lighter leaved hostas). It will bloom a medium pink, very soon.
I have the perennial begonias in this bed too. I do need to keep them under control in the spring, but that's easy to do. They bloom perfectly well for me and take drought or rain.
If you need some slightly vertical accent, consider a really nice japanese iris. My best ones are in the eco series as the foliage stays nicest, and they clump but do not run. Their blueish blooms with yellow would be wonderful with the vinca. I love the light green, neat foliage and vertical accent the rest of the year.
I also grow toadlily in shade. It will bloom fine, and can take some drought. It is the prettiest arching over hostas. Just so lovely and delicate the way it bobbles over top of the green. Anything green underneath it really shows off the flowers nicely. It also blooms late and there is a pure white, or the more spotted varieties of course.

GGG

I hadn't thought about chelone. I have some in another bed, but I didn't know it could take dry soil. That's a good suggestion. I'm growing my first trycirtis hirta this year from seed. Only one seed made it, and so far it's doing okay. I know what you mean about it looking pretty arching over hostas. I have it in another bed where it is doing that. I like the effect.
I've never met a dicentra I didn't kill, but I guess I could give it another try. NO - it would be pre-meditated, first-degree murder.
How well does the foliage of Japanese iris stand up after the bloom is over?

as I said, only that one chelone can take dry soil, and only dicentra exemia can take (and thrives in) dry soil.
The tectorum japanese iris "Eco" strains have beautiful foliage after flowering. I can have some for you if you choose to grow it.

GGG

If it gets a little morning sun..... One of my favorite perennials for a shady spot is Eucomis or 'Pineapple Lilly'. Not only can you get great purple hued and green foliage but they bloom late and last quite long and would look great spread throughout your bed with Vica around them. Oxalis also will bloom long in shade (if take care of) but may not be tall enough if you have dense Vinca major. My Hosta odorata and H. June are just now blooming and the ordorata sure smells great.