I was actualy wondering something like this as well.
I wanted to make an alt to just dinker around with my UI, but set him on a solo profile. Where all others are using the default.
And when I get a setup I like better than my default, Load the alts profile as the default.
It would need to encompass legacy ace 1.3 mods as well.
Something you might wanna try (it works for me at least) with the steps i provide but make sure you backup your WTF folder before doing this.
1. Delete all your ace addons savevariable files or if you are bold, delete the whole WTF folder.
2. Login to the game.
3. Start doing all profiles FIRST before any other setups.
4. Once done, do a /console reloadui so the profiles are being saved.
5. Proceed to setup the addons.
6. Once all done do a /console reloadui again finally save all the changes.
7. Logout and login to other characters.
From this point onwards, you should be able to have the "Copy" function of the profile working.
Repeat step 3 if needed.
Hope this helps anyone having issues with the profile.