Welcome to XMarks!

Unfortunately the work you are describing is much more than "finishing." I did almost exactly the same project a year or so ago -- purchased a sewn-up length of wool, pleated, with waistband and buckles. The original maker had worn it this way but I knew that wouldn't last -- the wool can't take the strain, it needs stabilizer and interfacing.

Here's my posted description of the work involved: Finishing a Kilt for Bob

Hours of work involved and if you're not doing it yourself, probably cost-prohibitive. But you might find somebody on the forum here willing to take it on -- not me, too many personal projects in the queue! Best of luck with the quest.