Pro Sites api? Allow our own custom checkout :)

Would you ever consider releasing an api for Prosites that would allow us to have our own carts for checkout, and on success activate the appropriate blog?

I tried patching some together on my own, and it just wasnt happening. Currently I have to collect payment and manually enter, as the prosites checkout confuses my "customers" ..

I would like to simply have an API that would allow me to, for example, post a subscriptionid/transactionid, renewal date, etc,

Would anyone else think this would be beneficial? Or is someone already doing something similar?