Anyone know of an add on where you can tag custom user fields? For example a users real name, instead of their user name

[RobinHood]

I have a custom user field where people can enter their real names.

It can be a pain remembering what certain peoples user names are, but I want to be able to still tag them if I know their real name.

Does anyone know of an add on where the tagging system could search both usernames and real names and populate the selection box using both results?

Something like this: