Originally Posted by BlazingPedals

Going to a smaller front wheel will make the bike twitchier by increasing the head tube angle, if that's your goal. You can also accomplish it by getting a fork with more rake. Do you have a disc brake on the front, or are you planning on losing a front brake?

Originally Posted by downtube42

There is the impracticality of having to deal with two sizes of tubes and tires. Not to offend with bringing up recumbents, but my reason for going from a 26/20 to 26/26 format was to avoid this particular issue.

Changing fork and wheel on a bike designed for symmetric wheel sizes is going to alter handling, and probably not in a good way. Head tube angle is changed. You could use fork rake to try minimizing that effect. You've also changed seat tube angle, which affects CG fore/aft. To compensate for that you may need to adjust saddle fore/aft and stem length. Those changes have their effects.

Having said all that, if the OP wants to fool around with this, go for it. It's just time and money. Nothing ventured nothing gained. Too bad most bike co-ops are closed, because that would be a good source of cheap parts and people who like to screw around with bikes.