Have you tried hostas?

Here's a link to some native shrubs that might suit your conditions.

You might also do a search under the parameters: plants cold shade wet

Here is a link that might be useful: Shrubs for shade.

Sounds like you're describing "Fern Heaven". . .and they
would be happy companions alongside Donna's hostas. . .as
for njtea's list, I heartily second the Clethra and the
Viburnum acerfolium, as well as the perennial Arisamea,
Aruncus, and Polygonatum, all of which I have had great success with in damp, shady spots.

Now, I have been trying to grow a healthy specimen of
Osmunda cinnamomea (Cinnamon Fern) for years, by keeping
a shady corner constantly soaked, with lack-luster results. . .could I, perchance, borrow a corner of the
north side of your house?

One gardeners "trash", another gardeners "treasure". . .

I'm with Carl. I would love to garden a spot like that. If you look at any of the garden books on native plants, that is their perfect condition. You have a chance to try ephermals like trillium, you could try primroses...
Try taking a look through Seneca Hills website. They have a few interesting plants for your site. If what you want is sold out, just keep it in mind for next January or look elsewhere.
Caladiums can be started in pots inside. Even that way, they will take their time to emerge. At least they did for me.
Besides ferns, also maybe gingers, glaucidium, Kirengeshoma, astilbe, cimifuga, ligularia or farfugium, sweet flag grass - Acorus, Hakonechloa macra or Japanese forest grass, trout lilies, false solomon's seal, heucheras, tiarellas, heucherella, Rodgersia, possibly angelicas, pulmonaria, toadlilies, elephant ear bulbs (not hardy), deinanthe, dicentra, hepatica, diphylleia, maybe kalmia.

Here is a link that might be useful: Seneca Hill

Thank you all so much for your suggestions-especially the idea that my "problem" is actually a potential treasure. I will keep you posted on my progress.

I'm always jumping up and down in frustration because so many shade plants require moist soil (I have dry shade).

How about astilbe?