There are a few different ways you can go about this.
I do know that some couples do a room block for their weddings which gets you a discount on the room but I am not sure exactly how that works as we aren't doing one. I am not sure if Escape weddings can do a room block or not though I want to say you can. Check Carrie's book. I'm sure it's in there.
As far as renting DVC points that is what we are doing. There are two ways to do it. You can find an owner on the DVC boards here or on other websites who are looking to rent their points out and contact them directly about securing a reservation. Many people have had good luck with this but it is a bit riskier too. Basically, in order to rent points, you have to pay the owner up front and you can't contact member services to ensure you actually have a reservation so there is some trust involved. Another way to do it is to go through a broker. You will probably pay a bit more to go through a broker but there is less risk involved as well.
We went through David's DVC Rental. There is a tool on the website that tells you how much a reservation at the various DVC resorts would cost for the dates you want. It's really easy. You fill out a form with 3 or 4 choices and David's charges a $98 fee to try to get the reservation for you. They generally get back to you in 24 hours or so either saying they managed to secure your reservation in which case you would owe the balance immediately to book it or they will tell you they can't get it and refund your deposit or offer you alternatives. If they secure your reservation the $98 deposit goes toward the total cost of the reservation. If they can't get your reservation they refund the deposit. The only time it isn't refunded is if they get your reservation but you don't take it.
Renting DVC points is a great way to stay at a deluxe resort for moderate prices. One thing to keep in mind is when renting DVC points you don't get daily mousekeeping like you would if you booked a regular room. I believe the deal is if your total stay is less than 8 days you get trash and towel service on day 4 and if your stay is more than 8 days you get a full cleaning on day 4 and trash and towel service on day 8. You can pay for additional cleaning services if you so desire.
Hope this helps.