Here's what I know (I don't vouch that this is 100% accurate but summarizes what I've heard from about 10-15 other people including Todd Peverill).
Pevs@AG is currently on leased land. The land is currently owned by an Arab gentleman that lives in the UAE or Qatar (middle east) and after 9/11 has issues getting back into the states. The land that AG is currently on is mostly zoned "Parks and Recreation" with Loudoun County. This type of land is generally hard to get "rezoned" to light industrial or residential. (Luckstone wanted to buy the field to turn into a large gravel pit but would have had issues getting it rezoned.) Now...the current owner of the land has leased it for like the last 20 years to AG (Jim, Jim Jr., etc.) but has recently sold the back end of the land (think Deep Woods) to housing developers. The main parts of the AG field will still be there. Pev offered to buy the land from the current owner, but his asking price for the land was ridiculous. As such, Pev and Todd went out and bought land near Gilbert's Corners on Route 15 and 50. (If you take Route 15 about 2 to 3 miles west of the Gilbert's corners intersection the field is immediately on your right...at the PW County and Loudoun County Line). I'm not sure of the business relationship between Pevs and AG and any contractual obligations that may occur after the new field opens. I speculate that both fields will remain open though.
What I do know, having seen the new field plans, is that the new field will be incredible. They're going to have 8 or 10 tournament airball fields (better for the PTS events!) of a quality seen at national events. They'll have a building with indoor plumbing, facilities, etc. to make concessions and running H2O easier. They'll have lights for night play on the tournament fields. They will have concept fields there, including a castle field sponsored by Tippman and a "town" field. The real upside of the new location, is that it sits on a better chunk of earth where there will be better runoff of water. VicodinES, who frequents here occasionally, is a geologist by profession and can tell you the makeup of the geology that AG currently sits on (good for a business like Luckstone to want to buy...not so good for paintballers) and why that's not desirable as it holds water and retains it on top of the soil. If you ask nicely he may tell you this in less than 3 minutes.
I talked to a guy at the field about a month ago that was doing the development over at the new field and he said it's coming along (grading, surfacing type work). I've heard that the new stuff could be opened as early as this fall, or as late as next spring. I don't know anything about the business end of this int erms of what this means for refs, field operations, etc. but what I do know is that this can only be good for paintballers in the area. Couple this with the fact there's a new Pevs field and store in Essex MD (that Brent and Kendra from Stafford are running) and you have lots of options for ballers!