Hi mate, check out the 'mega fishing thailand' website, there's heaps of options.
Or get in contact with Jean Francious, the guy is a legend in thailand, he has so many fishing world records its ridiculous.
Fishing one day at Bungsamran and predator lake is possible when staying in bangkok, i have been to both and cant reccomend them highly enough. You will come home with the sorest arms and catch fish you've never dreamed of.
If you are a keen lure fisherman, try and get out and do some snakehead fishing with jean francious,its all surface fishing with poppers and buzzbaits in any one of the resoviours scattered around thailnd (just like our dams).
Hope this helps
Robbo