I'm new to the forum, but I was reading a post earlier and now can't find it. Someone was looking for a battery holder for 4AA's. I didn't know which thread to post this on, so I chose general discussion. I checked out a site that this person may be interested in. It has the battery holders you inquuired about and many different types of surplus items.
I live in Illinois and visit their outlet with my daughter frequently. Just found out that they have an online page.
American Science & Surplus. Type "Battery Holders" in the search at top of page and see if that is what you wanted.
BTW, I've built several flashlights from "scratch" and really enjoy reading the modifications you guys make to yours!....Later.
Unfortunately, the Sciplus.com website doesn't display a picture of the 4AA-to-D battery holder. Is is roughly the same dimensions as a standard D battery, or is it one of those rectangular holders?
Here's a link to the page, for anybody else who might be interested: