I agree with this suggestion (somewhat).
The close-vote queue is continuing to swell out of control (56.1k as I type), so obviously some measure is needed to increase the rate at which they can be cleared. This is one possible method; others include accumulating unused votes to be used later (so as not to waste votes when one is cut off from SO) and just increasing the close vote allocation. I think this solution is the best of them so far.
I do have some reservations, though. As mentioned by @JanDvorak in the question comments, just get five sockpuppets up to 3000... My suggestion for this is to initially refund only a fraction of used votes. This could start at 1/2 (that is, you're refunded 1 vote for every 2 closed questions that you voted on) and increase to 1 (every successful vote refunded) as you keep voting in sync with the community. The sockpuppets could still be an issue with this proposal, but the gradual scaling-up allows more time for them to be detected and, um, moderated.
(Note: It is mentioned here that we could safely return to the normal 40-vote system after the backlog is cleared. I disagree, and think these measures would need to be permanent; what's to stop another backlog?)