Before anyone cries "IDIOT!" I'll be up-front and say I've not played a monk or FvS so I'm not as familiar with either class so I'm not sure how viable this would be but I've been kicking this idea around since I read the lammania release notes on the new FvS pre.
The basic intent would be a build that can intimidate, generate enough hate to hold aggro, have enough HP and AC to be a viable main-tank and throw in evasion as an added bonus. In addition it provides an added benefit to casters with the -2 debuff to saves and to melees with the potential fort reduction on bosses.
The benefit of the FvS levels is primarily AoV 1 to get the debuff aura and the fort reduction on the bosses that hit you, the benefit of the paladin levels is DoSII, Paladin saves, Aura etc and the monk levels is the wisdom modifier to AC and saves as well as the monk feat.
At the end of the day it might be better just to have a hate gen fvs doing the same job, not sure. I suspect at the very least the character would be pretty durable if not particularly good at any one thing.