Transforming my mountain bike into a long distance touring machine has gone well thus far. Here's what I've got:
It's almost ready to go except for the tires and bottle cages. I've ordered the tires already- 26" specialized 'armadillos'. There have been reports of people riding across the country on them with no flats at all.. I like that.
I had to fabricate this special bracket that bolts onto my brake mount in order for my rear rack to clear my brake calipers. This was the only real problem that I ran into with trying to carry gear on a mountain bike frame.
In-line barrel adjusters for brakes and shifters. I found that fluctuations in temperature throw off shifting and braking ever so slightly, and these are nice for minor adjustments on the road.
The shifters are bombproof Shimano SL-BS77's, the brake levers are Cane Creek Drop V's, and I put on a shorter stem for a minor correction in geometry, now I'm not as hunched over. The handle bar tape is Bontrager double gel.
One of my bike shop buddies recently said to me "I can't believe you are going to ride a MOUNTAIN BIKE across the country! And with THOSE shocks!!" Yes, I've decided to keep my huge front shocks even though they weigh a lot.. You never know when you will be riding along and hit something that makes you wish you had front suspension, like a huge pothole, or a cliff.