Hmmm...
Kensai/Cleric = loads of offense, not much defense.
Kensai/Mages can wear robes, IIRC, and Kensai/Thief can wear all kinds of armour once they get UAI, but Kensai/Cleric would be pretty much SOL in both armour and shields unless you did some serious fiddling. However, with DUHM, Righteous Magic, Kai and Improved Haste you could
really put a hurt out.
To be honest, I'd use SK to go multi, though, if I was going to do it - having fighter HLAs as well as quest spells would be very cool. On the whole, however, I think that Ranger/Cleric is the combo of choice if you want to do cleric dual or multi-class with a melee - access to both Druid
and Cleric spells is pretty hard to beat

I have given up all lesser evils as inadequate to my purpose.