Well, as strangely as it might appear, but the Pentax service can rock if you take care of it...
Last week my K5 and 5 lenses got a perfect AF adjustment by the Pentax BENELUX agent's service center in about 1hour and 15 min!
What happened is rather simple.
I wasn't happy with my DIY AF adjustment, so I contacted the Pantax service center and asked what it would take if they did it. So, they wanted to do it under waranty if it passed via an official Pentax reseller. No big deal, I called my reseller and he E-mailed the genuine repairing document I would need. Then I called the service center again and made an appointment at their location in Antwerp. Two days later I went to Antwerp and was received by a friendly technician who told me he could do the job in about one hour. And yes, al my 5 prime lenses where calibrated in to the camera's software and the body got a check-up and now the AF is spot on! I couldn't have done it better, absolutely not!
It took me 5 phone calls, two E-mails, about 118 km driving (= 7,5 lit. Diesel), 01:15 h waiting, a total of about halve a day...
Just call the right men, ask the right questions, get the right paperwork, make appointments, jump in you car and go for it!