First off, my apologies for asking so many questions over the past month or so - Duane you've been invaluable and I really really appreciate your advice. Here's my most recent project and conundrum:

I live in a loft with 12 ft ceilings, and their height completely dwarfs standard bookcases. I'm hoping to put up a row of bookshelves along a wall, and I'd prefer open shelving rather than traditional bookcases. What height should I be looking at? I have very poor ability to imagine how things will look if not in front of me, life-sized already.

Also, is there any chain store that sells shelving that is easily customizable? I have no idea how to go about looking to have something designed for me (Angie's List??), and would really prefer that as a last resort mostly because of my poor ability to know what I want until I see it and some concern over pricing.