Mountain Lion (purchased) cannot be downloaded via App Store. Help!

Question

I bought Mountain Lion via the App Store, and now I cannot re-download this now that Mavericks has launched. It is "not available in the US App Store," apparently.
I would like access to the software I purchased. How are other people fetching their (download-only) software they purchased? While the whole innovation of central stores IS THAT APPLE KEEPS MY PURCHASED SOFTWARE, if this is not the case, I'll need to keep local copies, and need advice on how to fetch my purchased software.

Answer 1

I had a shockingly, unacceptably bad experience today at the local Apple Store over this issue. Upsetting because uniform build quality and good service is what differentiates Apple from Dell, and creates the extra hardware expense.
For others who are having this issue:
Apparently Apple Stores do not have, or have access to, the "non-slipstreamed" (e.g. Universal) version of the OS X Mountain Lion installer that you and I paid for in the App Store.
If pressed, the only solution given is to create a backup disk (or boot-up USB stick) from Control-R on startup.
Said solution, however, will generate a boot image that is contingent and dependent upon the hardware on which it was created. Therefore, if you move from a Mac Mini platform to a laptop, and try to install the Operating System--which you have paid for--from this USB stick, you might not be able to boot the system.
The recourse given is to "call 1800-My-Apple," which may or may not have a charge associated with it.
Oh, and #5: Apple Store employees (not the Genius) may tell you you are violating copyright when in fact you are taking an action protected under EULA and Fair Use provisions (e.g. backup copy, one-copy-for-one-computer).
All in all, this has soured me on my upcoming Apple hardware purchase. LUCKILY for me, I might have found a copy of my Install OS X Mountain Lionpackage. Good thing I did not rely upon digital curation to maintain my digital purchase.
Lessons?
Make a copy of everything you purchase via the App Store. Even if it's a curated store, apparently there is no guarantee that your purchased software is retained.
Maintain multiple backups.
Be very, very careful when moving across hardware platforms with a Command-R-generated boot drive. Apparently this can create chaos. Silly me, I'd have thought the "full" version of the installer would be used when creating a boot disk via starting up in rescue mode.