I ran 27" on my old one, actually made up a set of 27" wheels for it, very eclectic - campagnolo c-record rear, schmidt dynohub front, on polished sun cr-18.

Something to understand about the brakes on these is it isn;t not the height difference alone, but also that the cantilever post spacing is narrower on the front, I measure mine around 58mm. Even if you stick with 27" wheels a lot of modern cantilever brakes won't work on the front.

But I set up my wife's 720 w/700 wheels and learned a lot about cantilever brake geometry. I finally got hers set up with some Tektro Frogleg knockoffs, but it was ugly.

Early Deore brakes, with threadless posts and the little black plastic toe in adjuster are the best - they allow up and down movement and they are designed so that the pad attachment point is directly above the post in a normal configuration. Modern cantilevers, designed for wider spacing, typically have this well inboard and, in addition to height issues, this is what creates a lot of problems.

Some of the modern brakes do look like they would work, so the situation isn't as bad as it sounds. Just looking at them, the Shimano CT91M looks like a good bet.

As for the bars, yeah, they are going. Funny thing though, they look a lot worse in the pictures than in reality for some reason.