For a FIRST kilt (only), I'd use a good heavy wool of the the hardest (least fuzzy) face, so as to simulate as much as possible the "feel" of working with worsted wool. Tartan is actually the best stuff to use. It is actually MUCH easier to deal with in making a handsewn kilt than ANYTHING else.

I'd also call The Scottish Weaver (in Charlotte, North Carolina, US) and ask what clearance worsted he has (if any). He HAD some Kelly of Sleat (in 2 different tartans) in 14 oz for a good deal, from an overorder. There MAY be some left still.