Dragon Warriors (
Magnum Opus Press), as featured in Ordo Draconis (i.e. the magazine of which you got issue #2 for free, if you're an EN World subscriber).
Originally published in the 80's, and reprinted by Mongoose recently... and with new supplements. Rules haven't changed at all, except for minor balancing and errata.
Also, in response to the original poster, I'd argue that 3e was the breakpoint for D&D no longer being the "same game", not 4e. 1e, 2e and BECMI D&D are all recognizably the same game, and almost interchangeable. You could run "G1-3 Against the Giants" with any of those rulesets without too much modification.
However, 3e was a radically different game to 1e/2e (and 4e is radically different to either). AC goes up not down, prestige classes, 9 levels of spells for non-wizards, multi-attacks for all classes, no level limits, massive integration of skills and feats, monster templates, unification of rules into d20 standards, OGL, etc, etc.