Language selection in admin logon?

Hi

I'm running a multi-language store with a vendor module allowing vendors to post their products on my site. I would like to offer them (vendors) a language selection during login (dropdown) so the admin section would show in their preferred language instead of the default admin language I've set.

Looked around but could not find any extension that allows to do this. Is someone using this or is anyone aware of this being developped already?

Running OC 1.5.2.1 (default template)

Thanks for your support

Cheers
Kurton