Well, I plan on having a few playtest battles myself tonight. I'll try a few at higher levels as well, just to see how it goes.
A single page (or two) Monster Guide would be very cool product. I'm visualizing something akin to the Monster selection in the OD&D books or the 1st ed. DMG, basically a big table of vital stats with a sentence or two description afterwards.
Modules could be a single page tops, map(s) on the backside. Something to be played in a single evening. A brief description paragraph detailing the hows and whys of the adventure. Minimal references to statblocks to keep it short with 1-2 sentence descriptions for each room in the dungeon/area.
Did I mention that I really dig this system yet?

Of course, I've always been a big fan of the "less is more" ideology. And with a 2 page rulebook...a single printed front/back rulebook...well, you can't get much less than that without just making up a game on the spot.
Edit: Oh yes, and spells - gotta have the spells so you dont have to lug around the PHB! Maybe two pages (one for Arcane, one for Divine) and only include "the essentials". Since everything is pretty much "in your head", a single line description of the spell would work out well.