Yeah, it's hard to beat the old Singers. I snagged an old 1950's model 99 on eBay for under $100 shipped. It only does straight stitches, but it really does them well, and you can punch thru several layers of nylon webbing and even belt leather.

Awhile back I made a sheath for a little fillet knife out of nylon webbing lined with pieces of plastic milk carton and it punched thru all four layers like they were nothing.