I've CS4 Master Edition purchased and registered in the UK, with a UK Adobe membership.
I now live and work in Canada, and have a (different) N American Adobe membership (for Lightroom).
I qualify for Creative Cloud in the UK, but can I join under my N American membership and be billed in $?
You would want to join under an Adobe ID associated with your current address. If you have a past Adobe ID with registered products that you needed to transferred over to a different Adobe ID please contact our customer service for assistance. The billing amount is based on the country you live. Payment is done monthly by credit card, not sure about paying in US dollars, seems like it would process payment the same as any other transaction on the account.