Wow Rob Bye...Since when do you need a certain size combination to use a tripod?
I'd have to go through past issues of the newsletter, but I believe that rule came into effect back around 1986.
Tendonitis is a perfectly valid reason for wanting to use a monopod. Go for it!
I've seen so many faux-tographers show up to major sports events with a monopod, only because they think it makes them look pro. It takes more than a monopod to earn a spot on the sidelines, but some people don't get that. That's the sort of scenario I was envisioning.
As that's not the case here, I'll second the recommendation for Manfrotto's 681. For lenses, 400mm or longer, that's what I usually use.