Purely as an FYI...
Visit to the still-new Immigration Officein Mae Nam on Samui today... Wow. As painless as any government interaction I have ever had in Thailand. In and out in 20 minutes. Air con. Smoking area right nearby. Comptent and nominally helpful staff. It might almost be worth it to come here and make it a day trip from BKK, considering the hellish experiences I and other members have had there... And my overstay and full-up passport? Handled discreetly and perfectly.