This has now been implemented and has gone live. The way this works:
Rather than tie restriction of profile change to the "View Billing Information" permission setting, it is tied to Create/Delete servers permission. It has now been renamed to "Create, Up- or Downgrade & Delete servers"
So if a user does not have that checked, they cannot access the create server screen (which blocks them from viewing pricing) as well as now preventing them from accessing upgrade/downgrade and the profile price is no longer shown in the profile details window
The existing Billing info permission does what it always has: It blocks access to the billing area under Account so users cannot see/modify billing details and past invoices.
We hope this does what you needed it to do :)