The biggest factor in making these wheels strong, reliable, and maintenance free is going to be the skill that goes into making them. The best money in my opinion would be put toward finding a good wheel-builder.
I have built several wheels myself, and I can tell you that it takes a feel for wheel building (which I don't really have yet) to make a solid reliable wheel.
If you do go to a builder, they will have their own opinions. If you'd rather do it yourself - here's a few recommendations:
for spokes:
DT aerolite are very nice spokes (expensive though) and they fit through standard hub spoke holes.
If you can afford them, they are the best choice - especially if you are going to build these up yourself. The reason for this is that with a bladed spoke, you can detect any spoke windup visually - so while you're truing your wheel you don't end up with all the spokes twisted.
Wheelsmith has some bladed spokes as well, but I have some and I'm not terribly impressed with the blading - it's not completely smooth.
If you decide to go for double butted, get 2.0-1.8-2.0 - not the really skinny ones.
I've used DT's which are pretty nice, but wheelsmith seem fine too.
With the spokes, the durability is going to come completely from the build quality.
Brass nipples are the way to go.
Get some spoke prep as well - will make your wheels stay true longer.
3 cross is the way to go.
I don't have any experience with those rims, but I'm slightly puzzled by your choice to use tubulars on a touring frame. Seems a bit inconvenient should one get a flat.
But you've probably thought that through.
Rim quality is much more important to wheel quality than the spokes, so if these are used rims, make sure they are perfectly true and in perfect condition.
Happy truing!