"the best option if I suddenly get the urge to cruise down a dirt road or explore a trail near camp"

That isn't true. One really needs to read previous 26" threads in the touring forum, then switch gears and read some 29er threads on an MTB forum, where the trendies in the MTB world are all agush about MTBs built on 700C rims. 700C is the hot deal in MTBs right now. Not as far as sales are concerned maybe but as far as cool and custom sales.

It also isn't true that 700c rolls better that 26". It is only true where bumps are harsh enough that you would go airborn on a 26" wheel, but get the gravity ride back down with a 700c wheel, which is a pretty small subset of terrain. But what is true is it is easier to wind the smaller wheel up, and the larger wheel is smoother.

700c wheels are very strong if good parts are used, and they are properly assembled. My wheel failed stories are meaningless unless all the circumstances are specifically known.

I have had trouble getting 700c tires in NA let alone the rest of the world. Anyway, just any tire is not what I want, I want a quality touring tire, and one pretty much has to carry those. I was toying with the idea of going 27" since it is trad. on touring bikes, bigger than 700c. And decent tires are at walmart. However, I am building the next bike on 26" because I have 32 spoke Rohloff in the rear. 700c should be 36 spokes, minimum. I think wheel size is pretty much a wash, there are pros and cons to any of them. Just about anything else than size is far more important.

"You can make a 40 plus spoke count by ordering a tandem hub and changing the spacing to fit your frame which isn't too difficult."

Or just buy any of several standard width touring hubs and have wheels built on those. It is somewhat mythful that there is an advantage to the 145 width. It is really there to allow a drum drag brake on a tandem, not because there is a structural need. I do want to be the first guy with a 165 mm rear end solo touring bike, just for fun.

"Yup. And then you can be in the position that I`m in now, trying to find rims for our tandem."

The solution there is to buy about 10 rims at a time, get a discount and you are set for ever. If I could go back and buy all those MA2s I left at Nashbar... By the way, which is your I would never buy rim? Cr18? I didn't know the Velocity was a nightmare, are you after the Mavic then?