I did this last year, but its pretty rare.
I posted what I was looking for on this Rent/Trade board, and on the other
DVC forum about a 14 months out from the reservation, and ended up talking to other owners that owned at the resorts I wanted. One wanted a VGC reservation for President's Day weekend, I wanted BLT the first week of Dec, both pretty tough reservations to get. Other owner had BWV which I wanted for same tough time frame. One reservation ended up being a few more points, so I paid him for them at a slightly-cheaper-than-regular-rental rate, and vice versa for the other; it was all in the spirit of doing each other mutual favors so just to keep the accounting straight. All four reservations happened to be within about a 3 month window, it was fun to be touching base with: Got your confirmation at the 11 month mark!
We didn't go with contracts or anything, but talked on the phone enough giving each other hints about our home resorts that we felt pretty comfortable and it worked out great. I probably won't have to go that route again; I was able to snag what I wanted at a less busy time at 7 months this year, and I may just pick up a small add-on before I need another Florida reservation 4-5 years down the road.
Logistically it might be easier for you to transfer one year's worth of points out, and another use year's points in, but that's if you want to use all your transfers for two years. I didn't, and it was simpler just to swap reservations in this case. With the high desirability of the 11 month window of GFV, I'd say your chances are decent if you look far enough out from the 11 month mark. It might be more profitable and easier for you to just transfer in some HHI points, then rent your GFV points out, then you'd have control over your reservation, too.