Alibaba or eBay. The former is the best place to find AGS-001 screens. Last I checked, both have AGS-101 screens, often only with the kit for modding a regular GBA (but it's a couple of spare parts at best, so you can always just put those away for safe-keeping). Still not much point in trying to recreate AGS-101 screens, since they're still out there as far as I know.
These LCD's are a great idea, but as TankedThomas already said, they can be found. I would rather see more housings for the original DS. There are very few now available compared to a few years ago. There are many OG DS's in poor condition that would just need to have the housing replaced, but that's getting much harder to do.
Just came across my old white GBA, and my failed attempt to manually backlight it. Unfortunately I bunged up the ribbon cable so it all got put in a ziplock for another day... that was a couple years ago, though. Whoops! I wish I had a donor SP sitting around, even a front-light - the prices a working one will fetch kinda kill my modding buzz, and it'll suck to kill a perfectly working SP even if it would be for a good cause, for me. Just checked Rose Colored, as I haven't done so since my failed mod, and looks as though a lot has happened since then. Though I was expecting to have all those parts still available from 'em.