Pentax should consider an "SDM Upgrade" program. Send your DA* in, get it cleaned and calibrated and have upgraded (stronger, faster) SDM motors installed. Get it returned in a week. They can follow the service models established by computer manufacturers - they ship you an empty box, you put your product in, and ship it back with pre-paid postage.
The price has to be right, of course, and if necessary Pentax should consider subsidizing the cost to make it palatable. It would be a PR coup and show that Pentax stands behind their products.
Pentax needs the financial stability to make this happen, so the faster you buy the K-5, K-5 and 645D and associated lenses in droves, the more likely they'll do this!