John> Can any pipers out there relate their own John> experiences of attempting to adapt to a John> folk-group style of playing.
Actually I'm going through that evolution right now. I was military-trained on the pipes and then played the last six years in a competition band. Both environments focus on precision, and are dominated by rules, conventions and conformity.
Recently I left the Great Highland Pipes behind to play the Gibson Fireside Pipes (mouth-blown smallpipes) in a ceilidh band. I'm finding the creative freedom I never had in the other, more strict, environment... and I'm having a ball. The ceilidh band setting is terrific for the style you mention, John... terrific, that is, if you are playing the smallpipes. But attempting the same on the GHB played with accompanying instruments is a far greater challenge, as explained well by others in this thread.
The closest style to "folk style" I can think of on the Great Highland Pipes is what we pipers fondly refer to as 'kitchen piping'. Wanna hear some? Take George Seto's advice and visit the East Coast! Technically speaking, the style would probably cause a piping judge to roll his eyes, but it's dynamite to listen to... somewhat like fiddle tunes played on the pipes with fiddle phrasing and tempo. 'Great stuff!