I've made another discovery:
This all has something to do with /data/misc/wifi/wpa_supplicant.conf. I'm just not exactly sure what it is yet...
Last night I wiped and resinstalled the original Froyo leak, which I had pretty good wifi with. I connected to my access point successfully, and copied /data/wifi/wpa_supplicant.conf to my sdcard.
I then restored my JRummy backup, with which I could not connect to wifi at all. I copied wpa_supplicant.conf from my sdcard back to the /data path, and wifi came right up! Copied the "bad" one back to /data/misc/wifi, and wifi stopped again...
I then compared the non-working wpa_supplicant.conf with the one that did. I could find ZERO differences. Permissions, group, owner were all the same. The data within the files were the same. Copied them to my PC and opened with Notepad+. I still could not see any difference between the two files.
I then took the good file, deleted everything within it, and wifi came right up. Tried the same thing with the bad file... no wifi. Keep in mind I was replacing these files in recovery so as to not interfere with anything else.
So, to sum it up, I now have working wifi, but have no idea why. It's been stable since last night with multiple APs. These files appear to be identical in every way, but obviously are not.