I've been doing a bit of reading. It seems that Jorpho is likely correct. There are comments here which suggest that attempting to access that "lost" memory as a RAMDisk may cause issues:
http://www.jensscheffler.de/using-gavotte-ram … sk-in-windows-7
http://www.osronline.com/showthread.cfm?link=178074
https://blogs.technet.microsoft.com/markrussi … hysical-memory/
I've always been a fan of fixing things that aren't broken, so I still intend to try this out someday. However, I'll do it after I've made a full disk image in case I encounter any problems. When I have something to report, I will post an update here.
Thanks Jorpho for your warning! You probably saved me from some headaches.
It looks like Gavotte RAMDisk works fine for Win7 as well as Vista and XP. However, it does lack some advanced features that other programs have, such as DataRAM's RAMDisk.
From what I've been reading, the general consensus is: If you really want to access that "lost" RAM, just run the x64 version of Windows. Until I have a backup image created, I intend to heed this advice.