On the Uillean pipes, it seems according to Tomas O'Canainn's book on Traditional Music of Ireland, that until the mid C18th, the pipes were tuned with two drones both tuned to D an octave apart and then a third drone was added, again tuned to D, an octave below again.

The standard pipes were designed early in the C19th with chanter, bellows, three drones and three regulators, though some have four regulators. The more normal setup, we are assured, is to have a tenor regulator of five keys from F# to C in the treble clef, a baritone for D to A in the same clef, and a large bass regulator giving G to C an octave below the tenor regulator.

O'Canainn argues that the extra regulators were only added to suit the nineteenth century ears.

Since the regulators can be tuned, as can the drones, it seems that since the chanter can also be replaced, the whole thing is hugely tunable.

And there was me thinking the fiddlers in Clare were doing it to shut up the boxes... Seriously though, I've seen pipers in Ireland tuning to all manner of keys.