Here goes.
For the past six months or so Iíve been running a 3.5 update of The Temple of Elemental Evil, with the characters currently about half through the second dungeon level of the Temple proper.
I wasnít very impressed with any of the 3.0/3.5 revisions of ToEE currently floating around the web, so Iíve been revising/expanding the original module as I go, usually just a few steps ahead of the PCs.
Iíve been keeping fairly detailed notes (room descriptions, stat blocks) in a Word .doc as I go and have been considering cleaning it up for anyone else who is interested.
If thereís interest, let me know. If there is, Iíd like some feedback from others who are familiar with the adventure as I continue updating the module, and revising the current update.
Here are a few of the major issues/ideas Iíve been grappling with in the course of the conversion, and some reasons why I embarked on this crazy endeavor in the first place:

1) The current conversions available here on ENWorld and elsewhere are 3.0, and not particularly inspired, having opted for a straight across conversion in most cases that leaves a lot to be desired. So, for example, PCs are still fighting unclassed bugbears in the bowels of the dungeon, then coming across a 50,000 gp magic sword in the next. The assumed experience/level progression in 1e (the big bad wizards and clerics near the end of the module are only level 9, followed by an encounter with a demon princess...) doesnít jive with 3.5. In fact, I fully expect my current group to be level 15-16 by the time they reach the endgame -- they were 3rd level when entered the Moathouse dungeon, and 5th or 6th when they entered the actual Temple. So as Iíve updated the adventure Iíve been keeping a running log of XP and loot, bumping up most monsters/NPCs to better match expected PC levels.

2) Just as the 1e level progression doesnít hold up well in 3.5, the adventure (great as it is) feels outdated in its design principles. Although itís not really feasible (or desirable) to turn ToEE into anything other than a dungeon crawl, room after room featuring identical bugbears gets old, quick. So in a number of cases Iíve strayed a bit from the published module (revising, rather than converting), subbing out monsters for more mixed groups. Thereís also a lot of the ďsave or dieĒ (or just, die) kind of elements that Iím personally not fond of, so Iíve gotten rid of some of that, as well.

3) Verisimilitude is distinctly lacking in some areas. The Temple itself, for example, includes quite a few large (or larger) monsters, but features a single unlocked means of access -- one that not only is too small for most of them but also leads through a wizardís supposedly secret quarters. Iíve tried to avoid modifying the maps whenever possible, but in that case, at least, was forced to add an additional means of egress on the first dungeon level. Similarly, thereís the issue of NPC A.I., so to speak -- or the complete lack thereof. It appears to be assumed that dungeon denizens will sit blithely in their own rooms as the party one by one destroys their neighbors, never investigating or mounting any kind of counter-offensive. In some cases this is fine -- the various Temple factions are often warring among themselves -- but in others is too implausible. So Iíve been building in contingencies and modifying tactics accordingly.

4) Iíve tried to expand on the action in Hommlet an Nulb, adding sidequests here and there, many based on encounters from the (quite good) ToEE computer game from a few years back. This added quite a few more opportunities for roleplaying before hitting the dungeon crawly meat of the Temple, as well as the XP needed so the group wasnít totally overwhelmed on entry.

5) Finally, Iíve been trying to work in some of the Greyhawk lore that has come after the original module was written, especially as it concerns The Elder Elemental Eye/The Big T.

Anyway, post is getting long so Iíll wrap up. Any interest? Any feedback? If so, Iíll post some more specific examples of what Iíve been doing.