Ben - regarding V-brakes and drop bars, there are a couple long-pull levers out there, and the best of them is made by Cane Creek. So, don't fret about drops and v-brakes, it's doable!
Regarding Sam vs. Joe... I think it comes down to a couple things:
- Are you planning to run fenders? If not, both bikes can fit a decent size tire, even the caliper Sams. If so, that'll reduce the Sam's offroad capabilities somewhat
- Are you a heavier or lighter rider? If you're sub-200lbs I wouldn't concern yourself with which will carry a payload better, as they'll both carry a lot.
- What percentage of off-pavement riding will you do? I would stick with the Sam if you're above 70% pavement, but no doubt the Joe will start to make sense as that number drops
They'd be such complimentary bikes as Erik has illustrated, but if that's not feasible for cost or space reasons, it's a funny thing: it's a heck of a difficult decision, but at the same time, you can't go wrong with either.