Hmmmmm ...... I'd generally agree with all of your points except one: when braking, the load on the front wheel can equal or exceed any load on the rear wheel so don't skimp there.
Aside from that Mavic Open Pros are NOT designed for loaded touring. Road racing components tend to use stronger, more exotic materials just so they can use less of them. The objective is something that is strong enough for road racing (a lightweight bike and rider on a closed circuit) with a priority on being as light as possible.
The Mavic A719s are nice but maybe overkill. For all practical purposes a pinned joint is as strong as a welded joint. And I say that owning those rims myself. But if you like them by all means go with that. I'm just saying you don't have to spend that kind of money for a strong rim.
Yup - MTB rims are generally better sealed than road rims but generally the rear axle sizes are also different so you may have to replace an axle if you want to use those XT hubs.
And definitely, regardless of the quality of the parts - its the guy that puts it all together that determines how well it'll stand up to extended use.
Last edited by Burton; 02-02-12 at 07:23 PM.