As Matt has said pipes/fiddle duets (and combinations of pipe/fiddle with other instruments) are ''not at all unusual '' and the various people mentioned especially the High Level Ranters as Colin R has pointed out pioneered in this.
I have played duets (and in bands) with a fiddler (Peter French though unfortunately he's still based in Hong Kong and me in the Scottish Borders!) This type of duet (and playing in a small band), though hard work is for me one of the most satisfying ways to use the pipes. However it's surprisingly difficult to find interested fiddlers. The smallpipes we find most compatible are the D NSP and D SSP where chanters are easily interchangeable in performance and the latter are excellent for playing in G. Also the ability to pick up the Border pipes is great when the ''folk band'' shifts up into ceilidh band mode. As for John's mention of A SSP's these pipes are (unfortunately?) by far the most prevalent type of smallpipe adopted by Highland pipers, and can sound nice with a fiddle and there's a benefit to the fiddlers who can easily read Scottish pipe notation without transposing. Maybe its an advantage to play with a non-dot-reading fiddler who learns tunes primarily by ear, like Peter. Of course the type of pipes to employ when playing with other instrumentalists all depends on the context of performance. Bill (Currently recuperating having just had to play with band at 4 Burns Suppers unfortunately duties involving haggis-piping-in mode) To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
