I began to think I’d misremembered the googlemail.co,uk thing or confused with Microsoft’s various email addresses which definitely did have both endings as searching on the web seems to find even Google denying that it existed however there are a few references to it like this one:
googlemail.co.uk, googlemail.com, gmail.co.uk & gmail.com are registered by Google having the following name servers:
Discuss web hosting related stuff here.
www.webhosting.uk.com
So I think it did exist ;(,
There are also a couple of reference to googlemail instead of gmail causing authentication problems (though they shouldn’t).