I wager not (judging from procedures at BKK and having done THS-BKK-REP last month). After being bussed from the PG hard stands to the international terminal (you'll have to wait for everyone on board barring VIPs to get on that bus), you'll have to clear Thai immigration and customs (don't know if you have to claim and clear your checked-in bags too or if they are just transferred to the domestic flight for clearance at your Thai destination), walk in the 500m overhead tunnel (hamster tube) to the domestic terminal, check in and then clear security (and the plane you disembarked may be right next to the plane you embark on!). I'd say 50 minutes is way too tight and not legal - it's doable the other way (domestic Thai to international) but barely.

[This message has been edited by terenz (edited Feb 24, 2004).]