The closest I've seen are the tables in the back of Serpent Kingdoms, which list things like ability adjustments, 3.5 LA, etc.
There is also the 3.5 Update Booklet on the Wizards site, which updates Monsters of Faerun for 3.5. Note though, that a lot of the monsters from MoF have appeared subsequently, and don't always correspond to the update stats, so a Tainted One might not look quite the same if it were to be redone. A combination of the update and the SK book would probably be a good bet.