I think 32 pages is a tad optimistic (and this from me, the creator of
Microlite20. Ha!), as folks will expect everything that's in the PHB, as least for a number of levels. I reckon a revised Basic D&D for levels 1-3 complete with spells, DM advice, monsters, treasure and encounter tables would make a terrific 128 page intro to D&D. That's the beginners/just getting started book. Like
ST Cooley's Basic Fantasy, but with everything you need to play in one starting book.
But they could also take out all the flavour text, hand holding and stuff that's there just to keep the folks who like to ask obscure rules-combo questions and expect the rules to provide the answer (like "can I think evil thoughts when I'm invisible?" or "Can I use featherfall to nix a monk mid-leap?"). These are the bane of D&D IMHO, and are the reason why the PHB is do darned big in the first place. But that's another rant for another time......
Anyhow. Take out all that and re-write the rules in a manner which respects the players and credits them with enough intelligence and freedom to think for themselves. Kinda like the SRD does, really. Or the classic Rules Cyclopedia. And you'll be there.
I do believe it can be done for levels 1-20 and keep a page count in line with the RC. After all, that book had perfectly serviceable monster stats and descriptions in 1/6th of a page where the MM takes up 2 entire pages for the same monster. Go figure
As has been said before, d20 Modern, Spycraft, Wheel of Time, Star Wars and a host of other (d20 and non-d20) products prove is can be done with in page count, and at a price comparable to that of the PHB alone. It's only "tradition" and an perhaps ill-perceived belief that it'll damage profit which prevents it, it seems.