Wow, thanks so much everyone for the amazing replies! I've found two good rates.

The first is consecutive Z6R bookings for the grande deluxe rooms as suggested by yycworldtraveler, which are suprisingly available for the dates I want. All-up including taxes this comes to 6000 baht / day.

Another is a "smart savers with breakfast" rate, for a deluxe room with breakfast but no High-speed internet (how much does this cost btw?). All-up including taxes this is 5200 baht/day. So the question is, is internet access and nightly cocktails worth 800 baht/day?

Thanks again guys