I really like the Qatar Q suites but you have to check flights carefully as it tends to come and go on some of the Bangkok legs.
(as an aside just flew in from London on the new Thai (well newly leased old plane) 777 that now has first class. There are two rows of business just behind first that makes that bit of business a bit more secluded. I thought I may treat myself to an updgrade to first on the way back. The web single fare in first is about Bht117,000. To upgrade from my business class ticket they quoted me Bht133,000!!!. This is obviously quite bizarre. Sent emails about this to three different Thai email addresses - waiting to see if they will respond).