definitely do some calling around. Tell them what you want exactly, and get the skinny on what THEY want price wise. If they can't do what your want regarding prices, look elsewhere. Just to let you know, markup on paper is generally 100% when you walk into a store. I know this because I sold lots of paper and ink at a (if not thee) major camera store here in LA for over a year, no, NOT Calumet. I don't say names .
try some sheets of the papers you're looking at, if you already haven't. Hahnemuhle makes sampler packs with 2-3 sheets of each in the package. 8.5x11.
but for an order of 30 rolls or so, you should not ask, but DEMAND a huge discount. just remember, if a place doesn't want to play YOUR game (and you have the cash remember), you can go somewhere else. Some call this cutthroat, I call it smart business practice. If you can get the same product from someone for 25-40% less than retail, why get only 10% off if that is what someone offers you? Leaves more cash in your pocket. I'd often give nice discounts up to 25% or so when I'd sell to large buyers of ink and paper. They appreciated it. And I told them what I was doing. I believe in transparency with business. I was told not to do this, I never showed wholesale price, but I'd let them know what I could do, and it was generally 10% lower than my co-workers. They then ASKED for me BY NAME when they came back to get more, because they knew I'd take care of them and get them what they wanted, when they wanted it.
Go with a company that cares, and GET NAMES. ALWAYS GET NAMES when dealing with orders on the phone like this. Names=buyer leverage. Names=you getting what you want, and not getting the run-around when getting status of your order.
But you probably already know this, so its old hat for you. I just hate seeing people lose money when they should stand up for themselves and their businesses. Especially when its photographers and artists, many of whom don't know much about smart business.
not saying that your not good in business . I don't even know you.
best of luck with your purchase though!
-Dan