[dragonwriter]

> Assuming your Monopoly house rules allow arbitrary contracts

IIRC, you don’t need house rules for that, so long as “arbitrary contracts” covers future commitments for things otherwise legal to exchange (you do need house rules for such contracts to be self-enforcing, though.)

[kqr]

Some house rules prohibit these contracts -- that's what I alluded to not recommending. Sorry, I was unclear.