New answers tagged osr
The Dungeon Crawl Classics game seems to fit the above criteria, although it cuts off at level 10 as opposed to the RC's 36. It uses the RC's classes, including that of Dwarf/Elf/Halfling as self-contained classes as opposed to having racial mechanics. Ascending AC, attack bonuses, saves, all check. Fort, Reflex, Will saves - check.
There's a new version of Castle of the Mad Archmage, just released, that includes not only the first level of the dungeon, but also the surface ruins. It's available in print or pdf: http://greyhawkgrognard.blogspot.com/2014/01/castle-of-mad-archmage-now-available.html
Top 50 recent answers are included