Search Craigslist in the Little Rock AR and Wichita  KS area.  Lots of NEW leather hides around those towns. I picked up hides in LR 10 years ago for $50 each, with burn certs. Picked up 10 hides in Wichita for $100 each 3 years ago and they also had burn certs. Garrett leather at that. 

Bought a walking foot sewing machine and did the interior myself. Easy if you already have a pattern to duplicate the cuts. I took the seat covers off and separated the seams. Traced around the edges onto the new leather using chalk. Used pins to put everything back together then sewed the covers up.  

There is some gluing required:  eBay is your friend here. Buy some HHR upholstery glue off ebay and a spray gun from Harbor Freight to apply. $35 for the glue and $20 for the spray gun.  (Regular paint sprayer) 2 days and $500 worth of leather and you have brand new seats covers.

The neat thing about a walking foot is the speed and how evenly they stitch. I can adjust the stitches from nearly overlapping to 1/4 apart. Either way you can cover a lot of ground with the right pulleys. We are talking 5 -10 thousand stitches per minute. 

The different makes and models of sewing machines are much like cars, they all do the same thing. I have an old Juki 563 that was in a shirt factory in SC, it's old but still a very good machine. Make sure whatever you purchase it has the reverse: because every start and every stop you need to back up the seam at least 1/2" to lock the tread. You can crank it backwards by hand if you want but I would suggest a reverse. 

Most of the machines you will find are 110v AC belt driven and have a clutch to engage and disengage the drive. With this type machine its on / off  no starting slow and speeding up. When I first got mine (1996) it took a bit to get use to sewing @ 5,000 stitches per minute. The walking foot pulls the material under the needle very quickly when you space the stitches to 1/4 and your finger will not even slow things down. On more than one occasion I have sewn two pieces of 1/4" oak plywood together just for fun.  

Look around and try to find a DC drive with a rheostat so you can control the speed or plan on converting a 110V AC machine to a DC servo drive. I promise you a variable speed machine will decrease your learning curve exponentially. 

Like Ford said you can have a color choice when you buy a modal A: Black.

All my thread is the same color black: I buy per-wound bobbins and use thread size 92 UV treated and bonded. The bonding agent helps lubricate the thread as it passes through the needle's eye and fabric. Using only 1 size thread make it simple to set the tension on thread lock. Set once and forget it. 

I seen some really good machines on craigslist for less then $500 as there is not a huge demand for this type machine, I actually tried to sell mine 5 or 6 year ago.  Listed it on my local craigslist and never received a call or email. Kinda' glad I kept it now, as I updated the interior of N6090S to leather 2 years ago. 

Dale

PS: HERE is the FAA Flammability Testing Requirements in case you want to check your materials.