Upgrade front calipers

[andypont]

I am looking to have a brake upgrade in the near future, and fancy some atr twin pots (or similar). Preferably with carriers, for future use.
Initially I would fit them with my lude carriers and keep standard discs, but with a view to larger discs when they need replacing.
Does anybody have any or know of any for sale? Ideally ready to fit, but I wouldn't mind having to do a refurb before fitting.
Thanks in advance.