It's gonna be hard to find one manufactured by a hunting company.
My suggestion would be check withyour local heavy equipment rent/sales place and check out a harness made for use by linemen, or telephone workers. I havean apache harness rated to 400lbs that I usedwhileI was inconstruction and still use to hang stands and do tree cutting (has real linemanrings on it, not the cheap crap given out by stand makers).
Of course these won't be camo, most are yellow, green, orange, and some come in black.. I found apache harnesses still for sale at themanstoreonline.com Just be sure to get a tether that will hold the weight too.They are a little bulkier than other harnesses sold just for hunting.

Beware these won't be cheap, but it's worth it.