I've only made ONE leather kilt, and there is a HUGE difference in making them as compared to the "material" ones. Here are the things to consider:

1). There are leathers that are MORE than heavy enough for a kilt that are not that thick. With the layers in the pleating and the dual aprons, you really don't need much.
2). There SHOULD be a whole lot less sewing with leather than with material. A properly treated leather will keep its form, while material wanders. That conservation in thread actually makes them easier... not harder.
3). The areas of attention for sewing are limited to the hips, taper, and waist. Remember that the thread MUST be synthetic. As natural fiber threads contract and expand... so will the leather... to extreme!
4). The front apron is a HUGE problem with curling at the tips. A simple traditional tapering, a proper sew-up to hug the edges, and a wider apron will make this problem non-existant.
5). NOTHING is easier than the care for a leather kilt. If you've ever had a saddle, then you'll know that an ounce of prevention is worth a pound of cure.
6). Take your time when making a leather kilt. IF you're using a machine, then you'll go through a few needles since the leather will dull them quickly. The power of the machine is a non-factor. The needles and the slow speed of sewing are the tricks.
7). Would I make another leather kilt? That's an emphatic YES. The thing took me no time to make, and looked GREAT with the formal pleat depth, formal pleat width, and the three buckles.
~Think about using a suede leather when you do one. It's an unbelievable look in the daylight. You MAY even be able to find a suede with a "backing". This is usually a thin, woven backing that's soft to the skin.