I should have been clear and specified German Hefe.
If the yeast takes weeks to drop out, I'm guessing the flavor profile will gradually become less and less banana/clove-like.
This is what I'd like to avoid, although I don't think the keg would last more than 3 weeks anyway. Perhaps tipping/shaking the keg at the 1 1/2 week point would be sufficient to maintain the flavor profile.
Interestingly, when an Army-acquaintance of mine was stationed in Germany, he drank mostly hefes. He said it was always served from a bottle. Hmm...
On another note, do you keg-carb the hefes for a longer period, or at at higher rate/vol?