I don’t know much about this, except that it seems generally well-regarded, and it might satisfy Russell as a 3e-like system without all the cruft. I’ve read the Microlite74 rules, which take this and trim it down still further to make it more like a 0e retro-clone, and they seem pretty solid, though you still need a copy of some version of the SRD, 3e or the like for things like equipment lists and magic items.
Microlite20 | The smallest thing in d20 gaming
Microlite20 is a minimalist role-playing game designed to be usable with the majority of d20 supplements, rules and adventures with little or no advance preparation. The rules for character generation, combat, magic and level advancement take up a single sheet of paper, meaning it is perfect for introducing role-playing to new players, gaming one-shot adventures or tailoring into your own game system. Downloads PDF editions of the rules, supplements, adventures, including pocketbook editions.
Tales of the Rambling Bumblers 
Microlite20 comes highly recommended, but then I’m biased considering I’m the one what wrote it.
It’s d20/SRD stripped right down to the core with a simplified (and, IMHO, brilliant) skill system and a hit point based magic system tacked on. As it still uses Hit Dice, hp and damage rolls, 3e D&D monsters and adventures can still be used pretty much as-is, or with the minimum of conversion. Which is nice.
As M20 is so small, it’s ripe for hacking and generally using as a core for your own homebrew systems too. There’s a very active Forum where lots of like-minded system hackers post up their rules ideas, campaign settings and innovations. The cream of the crop gets promoted onto the Microlite20 front page by yours truly.
If you want to know more, just ask 😀
I’m not sure. Do you *really* need an equipment list? Just let the characters buy whatever they want and charge a few gold coins for it. Done. The prices for the expensive stuff — weapons and armor — are listed somewhere, if I remember correctly. And you can just make up magic items.
I guess my point is this: You need rules for the interesting parts that everybody needs to be aware of.
Nobody at my table enjoys buying mundane equipment, so those lists are not necessary. Everybody just has a lantern, torches, rope, backpacks, bedrolls, crowbar, shovel, etc. We never keep track of that.
And we don’t need magic item lists, because the DM controls how these get into the game. We find what she places there, and therefore only she needs to know, and can make things as she pleases.
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I don’t know about M20, but M74 doesn’t have a list for the big-ticket items like weapons and armor. What it has instead is a really clever pick bundle A, B, or C of standard adventurer’s gear, but I can’t see running a campaign with nothing more than that and winging all the prices.
And for 0e compatibility, I think you do need a list what things like Drums of Panic or Mirrors of Life-Trapping or even more mundane things like Boots of Speed do, even if it’s compressed to just a sentence each. You could say that the GM could just make up all the monsters, too, but M74 devotes almost a page to them.
I keep a copy of M20 in pocketmod format in my backpack at all times. Just in case I want to run something quick and dirty with someone. I’ve also used it to play some quick and dirty fighting miniature games with my six year old son.
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