Request to increase custom domain account limit from 500 to 1000

I have a custom domain setup in Live Custom Domains for the single purpose of Signing into Windows 8 tablets.
I have around 1000 (starting qty) Surface RT tablets that will be managed and I need to create Live IDs for each.

FYI: the Custom Domains has a limit of 50 accounts. The page notes: "You can have more accounts for free. Contact support to make this request.”.

I have no need for email or any other features. Hence I am not interested in Office365. 

In fact Office365 does not give me the LiveID i need to sign into Windows 8.

(So if you suggest Office365 as per your script I'll assume you're not reading this.)

I DO need a way to create 1000 LiveIDs easily.

Please PM or email me and I'll give you details of the domain.
PS. I've sent this through my PAM, a technical contact for our Surface project and also rung support. None of whom know what I'm talking about.

Thanks

Andrew