Air Koryo has FNJ - BKK - FNJ flight to Bangkok on Thursday and back to FNJ on Friday ( FNJ's Pyongyang of North Korea ) but I would think its a lil. hard for you to find any route Air Koryo will be flying to for you to connect to Bangkok , they fly TU - 154 ,
The 2 airline which might have cancelled are Balkan Balgaria as well ( in my time table ) but they have couple of stop before BKK - SOF. Another airline is Aeroflot from BKK to Vladivostok ( VVO on an IL62 ) but as you have said they might be cancelling their flight
Another choice you might have is to fly to Luang Prabang of Laos and fly into Chiang Mai on Lao Aviation Yak - 7 ( I think Chinese made ) and then another flight to BKK
Any of these flight sounds crazy doesn't it?