We are a bad group of people to ask because we have already bought them.
If we really wanted 4WD we would have bought Subaru's or Mitsubishi's, easy as that.
Ask the people who decided NOT to buy an MPS what they would do if 4WD were an option and I think they would pick up a lot of sales.
As for me, if the MPS had 4WD as a $5k option then I would have taken it for sure. $10k is too much tho.