One thing to keep in mind about your tour is that for the most part, there isn't much camping in most of SE Asia. It really isn't done, it's even unsafe in many areas (due to unexploded ordinance) and the guest houses are incredibly cheap. As a result, you should plan for this as a credit card tour -- i.e. bring the minimal amount of stuff.
Even if you do plan to do some camping tours, you have many options:
• Salsa Casseroll
• Surly Cross Check
• Surly Traveler's Check (a CC with S&S couplers)
• Ritchey Break-Away (another separatable bike)
• Jamis Aurora Elite
• Kona Jake series
• on the higher end, Co-Motion, Bilenky, Mercian
• on the "throwing away money" higher end
, Seven and Waterford
• if you are interested in folding bikes, Bike Friday
If you do a heavily loaded tour, you can easily use any of these bikes with a trailer. Most of them are rugged and have clearances for wide tires and fenders. (Plenty of people have had fun tours without needing the Ultimate Touring Machine.)
What you may want to do is have two sets of wheels, one heavy-duty for touring and one for performance. You may also want two stems or stem positions; one relaxed for touring, one lower / longer / more aggressive.
That said, I do agree with late in that these bikes will be more responsive than a true touring bike, but won't feel as snappy as a typical road bike. This should be acceptable as long as you don't plan to do fast group rides.