It is really not too difficult to "convert" (basically shorten) a tweed sport coat for wear with a kilt. The only issue may be the placement of the pockets. If it is a patch-pocket type where you can simply remove the pockets, then such conversions can turn out really nice otherwise there could be a problem with cutting through an inside placed pocket with very little room left for the pocket and funny looking placement of the pocket flap on a shortened coat.