No, there is no easy way to do this, since income and deductions are combined on a joint return. One way to do it is to prepare two mock married filing separate returns, and then apportion your refund/tax due on the joint return based on those results. Example: Joint return, refund of $1000, MFS return 1, refund of $600, MFS return 2 refund of $200. Spouse 1 would get 3/4 of joint refund, spouse 2 would get 1/4.
