Victorinox uses ballistic nylon, although they don't indicate the denier. I have the WT large cargo duffel (listed at 21x12x10) and like it. Doesn't retain its shape too well if not fully packed, and the shoulder strap isn't great. Otherwise, solid duffel. You'd probably have to look for closeouts in black, which are scarce.

Tom Bihn has several products that don't quite meet your size requirements (night flight is 17x10x9, Aeronaut 30 is 19.7 x 12.6 x 7.9), but close, and they all are made with 1050D ballistic nylon. Night flight is right at budget.

You could try Red Oxx, although they seem to use Cordura, not Ballistic. Sunchaser and Safari-Beanos Bag PR4 are both 19x9x9. Slightly over budget, but not by much.

On the 511 stuff, looks like the NBT Duffle MIKE could fit your needs. 1050D and 19x10x10 and black, although it definitely has that "tactical" look. Well under budget at $75.