Renting/Hiring Builders.

This idea struck me when I got to Th9 and most of the times my builders are free. When I was in lower Th's I was short of builders.
The idea is that when a player reaches an Xp of 100 or so.. He should be allowed to Rent his builders to clanmates(Xp 100 because any player could create another account just for the sake of builders).
While renting, the player could do a business himself demanding For some amount of resources or gems according to the period of hiring. The players, both renter and hirer, can be made not to leave the clan till deal is completed. Next update with builder hiring could be a fun and a surprise to everyone. You could also add that player can hire after some Th lvl only maybe Th8 or Th9.
I'm sure this could be a great update.

easily exploitable and is ruled out.

resource trading is ruled out.