Yellow archangel or Lamiastrum is an agressive ground cover in dry shade if you can provide some occasional water to get it going. Repeated glyphosate (Roundup®) applications are a control around the edges where you want it to stop!
Pachysandra in sandy soil through the winter usually has a tough time. Lily-of-the-valley is more dependable.

Here is a link that might be useful: Yellow Archangel

I also live in Michigan, by Manistee and have a serious sand mix. This fall, I'm gonna try moving some natural growing stuff that seems to do really well all over the place on our back property. We call it "teaberry", but I think the technical term is "Gaultheria procumbens". I'll give you some to try if you want it for postage.

It seems to do well as a natural ground cover, the berries are edible (kinda light, minty flavor), and with our "high and dry" sandy area it thrives all over the place and spreads into little pastures throughout the woods. I think it does best in part sun and/or dappled shade (but not sure). And I read that it's a slow spreader.

Just a suggestion...

Here is a link that might be useful: Teaberry

Horster, I do like the Lamiastrum and don't have a problem watering it until it's established.

How do you think lamium or vinca would do there?
Sweet Woodruff (too dry?)
I wonder if there are any ornamental grasses that would do ok in a partially shaded area.

Shadara, we're in Cadillac area, so not that far from you. I'm sure we have some of that growing on our property (we always called it wintergreen), maybe I'll try transplanting some and see how it does. I hear the grouse like it.

Honestly, I have no experience with sweet woodruff as it doesn't do well in my part of KS. I can tell you that Vinca minor needs consistent moisture to be happy and spread. I might add that wintergreen failed for me even with the addition of acidified compost since KS soils here are high pH and I couldn't get my soil acidic enough. I wish I could grow it! Neat plant! Flowers and berries on the same plant. Definitely likes acid soil.
Yellow archangel can get out of hand without control (glyphosate). Another one similar is Bishop's weed, Aegopodium podagraria ÂVariegatumÂ. Both can handle dry shade ONCE ESTABLISHED. But,there is nothing there in the winter like there would be with wintergreen.
Grass wise, you might look at Japanese Forest Grass or some of the sedge grasses that like shade (Carex spp.).
Hortster

Wow chez, that's kewl... we're practically neighbors, LOL. (just hit M-55/M-37 area yesterday huntin' morels. :D )

You could try creeping myrtle (?) since it seems to do ok on a rocky NE slope here by walkout basement (pretty shady). However, I realized it doesn't do as well in this location for erosion control. The storm we just had seemed to wash half of the 2 yr old plantings down to the bottom of the rocks/slope. :((

What about wild violets? They are "everywhere" right now no matter what kind of light they are getting? I'm thinking of borrowing the yellow variety I saw while shroom hunting (would go great with the standard purple).

Creeping myrtle IS Vinca minor. Experiences are different in different areas. In MI your annual rainfall may be much greater than ours (here, typically 2 7-29" per year, however, very sporadic - we may go for one or two months without significant rain causing damage to V. minor). My statement that, for Vinca minor to do well it needs consistent moisture is that a newly planted batch hitting a two month stretch without rain in a sandy soil would suffer greatly HERE. Having said that, if it had been well mulched it would have helped to ameloriate this, but not totally prevent damage without supplemental moisture, whether established or not.
If you are looking for a tenacious ground cover that will stare in the face of drought while living in dry, sandy soil in a shady area, either shadara's violets or yellow archangel or bishop's weed should work. However, keep a good supply of glyphosate on hand to keep these in check!
Hortster

Well, I think my hillside is going to look like a patchwork quilt by the time I'm done! I'm trying lots of different things to see what works best.

So far I have two 50' rows of Lily of the Valley, about 6 rows of pachysandra. I transplanted a patch of bishop's Weed, a patch of lamium, a patch of sweet woodruff and a creeping phlox in one of the sunnier areas. I ordered 100 liriope as I read on another post that it does well in dry shade and the nursery that I barter with has a big pot of lamiastrum so I think I'll get that too.

I am mulching everything with straw and/or wood chips and will try to keep it watered this summer but don't want to have to mess with it in the years to come.