I'm getting answers to this on the MODx forums, but thought that other Foxy developers might find it of interest (or have suggestions) too.
http://modxcms.com/forums/index.php/topic,29480
"I have a client who has seven separate logins to manage his store. (MODx, FoxyCart, Quantum Gateway, Merchant Account, Gmail for Business, Supplier, and FedEx.) I want to place all these links on one page for him..."
Have you seen FoxyBack - its only in the alpha stage, but it might make one less login for your client...
I have seen FoxyBack and love the concept. Its too early in development for me to start using it for a client though... It'll take me some time to sort out how to install and work with it.
Mallmus, you might be interested, its pretty easy to get it going. I added it to the wiki.
http://wiki.modxcms.com/index.php/Customizing_the_Manager_Homepage