Mismatched wheel sizes on bikes is so stupid.
Why?
In this instance, the BB will be raised and any height in the bars will almost entirely be negated by that. It's a non solution. Get bigger bars, or ride a 22" bike.
Even when a frame is designed around mismatched wheels, it doesn't solve anything, in my opinion. For instance, the obsolete 69er MTBs might allow a rider the ability to barrel over terrain with the 29" front wheel, while affording him better, tighter corner capabilities with the 26" rear wheel. However, some tweaks to the frame geometry--like a short rear end, longer effective top tube, lower BB height, etc.--will give him the same advantages with two equal sized wheels. Also, carrying two different sized tubes is a pain in the ass.
That's my basic interpretation, anyway. I feel like the only place for mismatched wheel sizes is on cargo bikes.