Sorry this goes a bit away from original topic. And if you go to the Chiang Mai meeting, I´m sure you will hear something similar.. but one of my best trips in that region was like this (in Nov/Dec 2005):

From Thailand, south from Bangkok along the coast to Cambodia (the road east from Koh Kong was an off-road riders paradise, but unfortunately they paved it!) and then Sihanoukville, Kep, and Bokor hill station on the coast. Although I´m not sure, if you´re allowed to ride up to Bokor any more, as they started to build some fancy hotel there. And then to Phnom Penh, a really nice capital, even though I usually don´t care so much about big cities. Then head northeast to Laos border (check if you need Lao visa from PP, at least for us it was not available at the border) – but if you haven´t visited Angkor temples, then well worth making a detour around Tonle Sap lake first, there´s the floating villages on the lake, too. They also sell huge spiders fried as snacks near Skuon, north of Phnom Penh! If time permits, you´ve got many nice side road options to take in that region as well. Mondolkiri and Rattanakiri provinces close to Vietnam border offer some challenging riding, too, especially if you´re on big bikes.

In Laos, chill out with backpackers at Si Phan Don, very nice islands on the Mekong river, then north to Vientiane, then Vang Vieng (the road goes through some REALLY fantastic mountain scenery!) and Luang Prabang, with lots of beautiful temples... And from there, charter a river boat, ´slow boat´, to take riders & bikes on a 2-day cruise north on the Mekong (it requires some hard negotiating at the boat landing, I think we payed about 250-300 USD, we had 5 people and 4 bikes – just remember loading/unloading of bikes to those boats is tough work, and must be included in price, or they´ll charge you extra!) Boats stay overnight at the small, remote village of Pak Beng, then reach Huay Xai the next afternoon. From there you´ll be able to cross into Thailand (Chiang Khong)... and then there´s still the mountain roads of North Thailand, surely among the best in the world.

We only had about 3 weeks for the whole tour (only some 4000 road kms, but spend at least double that time, if you can!) and especially the main road through southern Laos was not the most interesting... and I´m sure we missed a lot of fun in the northernmost part of the country as well. But I still think that river cruise was really something else, and overall the route went through some amazingly different and beautiful areas. Should be do-able the other way round, too. I did this on a rented bike, but the bike was actually rented from my friend, who lives near Bangkok, and he was with us on this tour, so he handled basically all bike paperwork at the borders. My understanding is that this should be possible on your own bike.

But this trip was 7 years ago already, so will be good to get more up-to-date info about the whole scene from others.