Heee. At the risk of giving annoying unwanted advice:
The place to look for building parts is Sweets Catalog--Google's indexes are full of building product spam, and it's hard to find the right keywords. Usually local libraries have a copy of Sweets (it's huge), but part of it is online at McGraw-Hill. (You may have to register.)
The usual industrial solution to your ceiling space problem is a roll-up or fold-up door. (The fold-up versions can include windows.)
The Usual Suspects (Jeld-Wen, Pella, etc.) as well as numerous smaller firms make leaf doors to order in wood, metal, and fiberglass.
Advice unasked