When I say 'single payer' (or payor as an en_UK spelling might prescribe) I mean a system with the following features:

    * Everyone is covered by one pool
    * The pool is funded externally
    * absolutely no incentive to defer detection
    * absolutely no incentive to defer treatment
    * absolutely no incentive to defer care
    * because everyone will be covered by the same system in the future.
    * Competition can still occur as far as offering services /to/ the pool.

Compensation for services will probably be some form of rate per area determined by an auction/bid system in advance.