Hi flywithsean,
Sure! The XML file still exists but is placed in another location!
You'll find the "xmlout.xml" file there:
C:\Users\{username}\AppData\Roaming\mGalaxy (Win 7)
C:\Documents and Settings\{username}\Application Data (Win XP)
Attention:
Those folders are hidden by default.
To view them, go to Control Panel > Folder Options > View > Advanced > Show hidden files and folders
One last info:
If you were to install a new mame version the xmlout.xml file would have to be erased manualy!
mGalaxy would build a new one based on your new mame version.
So, each time time you upgrade mame you'll have to delete the previous xmlout.xml file which otherwise wouldn't be updated to the new romsets.