personally, I have a problem with a business running a list out that far. Close it off, and take as long as you want to get through what you have now.
Continuing to add customers to a 10-year wait is asinine but as long as you're not taking a deposit I guess it's between the company and the future customer.
Cue builders that make you put down a deposit for a five-year wait should be paid a visit by the FTC, or at least their state's gaming commission because at that point you're basically doing an illegal lottery.