It's just my opinion, but I doubt that ANY U.S. manufacturer is going to give you "wholesale" pricing like you'd typically expect in retail. A company like House Handle in Cassville Missouri is a family operation and they produce quality handles at amazingly and ridiculously low prices, considering. For the price they charge you'll pay the same for a Chinese import. The point is that their margins are probably pretty tight already. They may give a discount for bulk, and I bet they would. I've bought 4 handles from House in the past month, the quality far surpasses their relative cost. Same story for Tennessee Hickory. I've see people reselling House Handles online for a 100% markup on ebay.
Depending on how big your bulk order is will dictate how much of a price break you're going to get. Where you'll shave a lot of your cost is on combined shipping. Good luck Mike. I'd be interested to know how this turns out later, if you don't mind updating us on the path you choose.