The Leupolds are the standard dovetail base on the front, and the windage screw on the base in the rear? I never liked that style of base, they look good, but that's about it. You could try two extension rings, but for what that would cost, you could just get a different set of rings/bases. You can get the Weaver extended front base or the Leupold Rifleman weaver style bases, as the front base has two slots on it to help with spacing, but it's only about a 1/4" of space, and you'd still need an extension ring.
If an extension ring won't help, I'd get a one piece base that takes weaver rings. Then you'd have multiple slots for the rings. B-Square makes them, you can get them at Midway USA or at Natchez Shooter's Supply. They are cheaper at Natchez, but Midway has superior service if you have any problems. Only cost $6, it's an aluminum base. I've used them several times, as I like the multiple slots myself. Then you can use any brand of weaver style ring that you want to.
The only other one piece weaver style bases you can get are tactical bases. Tactical bases are usually higher than regular bases, because of the bigger scopes that are popular now, so you may not need high rings, but you'd have to ask the company that makes the base. They are very high quality, and you'd know it too, as they generally run $30-$130 each, depending on the brand. There is a company that makes some of the OEM bases that come on tactical style rifles, I think it's call ECW. They sell factory direct on eBAY, if you go to scope mounts, type in Remington 700, you should be able to find them. I used one of their bases on a Savage tactical and liked it very much. Cost $30-$40 each plus shipping.
