Integral Designs Vapor Barrier socks as waterproof oversocks.

That is not the usual purpose of VB socks, but you can probably seal them to make them waterproof if desired. Of course by nature these would be non-breathable. On the bread bags – usually you put them between a liner and your sock. But do try them out. This (as well as the gaiters in you other thread, and about the easiest DIYs possible. Why not get some material and try things out?

Putting a sock over the bread bags would make them less slippery, but the point is to put them over my socks mostly dry when walking in snow with trail runners. I'm not talking about using the vapor barrier socks as actual vapor barriers but as oversocks in non waterproof shoes.
I can deal with with them not being breathable and if it's cold enough I can wear vapor barriers under the non breathable oversocks to keep my socks dry.

I really want to get into myog, but I don't own a sewing machine and my sewing skills are limited to fixing holes in clothing.

Yes they will work at least in theory. I use a similiar setup with MYOG PU coated nylon. Works very well even without breathing. My only concern would be wear. My original cuben version shredded after only 20 miles even with a light sock on the outside. I had even shorter life with bread bags which is why I made these in the first place. The PU coated nylon seem to be holding up well with no visible wear after almost 100 miles.

I've not found the ID vapor barrier socks to be waterproof or vapor proof. When worn as a VB inside cross country ski boots, they tend to wet out my wool oversocks with perspiration. When I've looked at the moisture patterns, it doesn't just seem to be the seams, but rather that the material itself is wetting out. They're also pretty slippy, necessitating periodic sock readjustment. This coming winter, I'll try re-treating them with silicone/mineral spirits to see if that improves performance. Or I may just go back to bread bags, which always worked pretty well for me.

I've used the for the very purpose you speak of and I wasn't nuts about them. The seam runs right under my foot and it wasn't long before it irritated my sole. I've thought about using neoprene socks but I bought a pair and then lost them so I've never actually tried it.