I'm toying with the idea of a Hope V twin with E4 caliper on my road/commuter bike. However, it has IS mounts and the forks are limited to 160mm rotors.
I don't think the E4 caliper fits around the A type mount. I hope someone will tell me it does.
But this got me thinking, why do the two holes on a disc mount have to be joined together? Once it's bolted in place, does it really need to joined? Couldn't you just remove the bit of the mount that fouls the caliper?