The location is about 5 blocks from a university so i'm thinking of renting out to students - or perhaps the school itself , they have bought up as much property as they can already.

Anyone have any experience in changing the color of the existing asphalt roof shingles without actually replacing them?

I never ever put drain cleaner down my drains.No, I don't snake between tenants, but I do run the water to check the faucets for drips and to make sure the drains are flowing like they should.I always fish the hair out of the tub and shower drains with a zip-it while I am in the house getting it ready to show.When a tenant calls me about a blocked drain, I will use a hose and bladder through the roof vent before I snake.

I don't know much about your business, but my suspicion is that you have a bunch of low-end rentals and that is coloring your perspective.

Stain it a color that your wife likes. 

It seems similar to Mt Airy in that it can vary so much block by block, etc, and I'm trying to get a handle on what areas / blocks of Germantown are stronger investments.

Also,I like a more soothing off white color like cream.If it's too bright it will look like a dentist's office and give people a headache.

The wife and I are looking in Keene at the moment, and are trying to stay away from the flood zones and the more run down blocks in north and east Keene as we get started.

Consider adding Skylight to bring light into the room BEFORE you close off the window.btw: color is drab IMO

Why are you wanting to use glass block?