low pressure, high volume air compressor

My application is a modification of one of my power hammers. I currently use a 3.25" bore cylinder at 100 psi on the hammer head and I want to go to 30 psi, say, with a 6" bore cylinder. These check out with P1V1=P2V2. I have one prototype hammer with a 6" bore cylinder driven by a 7.5 hp handmade piston pump. The pump moves a stroke for every stroke of the hammerhead cylinder. I'm looking for an alternative innovative continuous running pump feeding into a relatively small surge tank that feeds the hammerhead cylinder. Maybe contacting IR can shake loose some engineering info. The hoses need to be bigger, of course, as the cfm rises, but probably about 2" or a bit less id will work. The 6" suggestion reminds me of a silage blower in my old days in Minnesnowta. Seems to me that piston pumps are good for low volume and high pressure, but perhaps not vise-versa. The vane (?) pumps that are now rented by construction equipment leasers have a 100+ hp diesel and they can crank out way over 100 cfm at 150 psi all day to run jack hammers. I'm thinking maybe a smaller scale version of this technology. Thanks for your ideas. www.ironkisshammers.com