I did it, I did it. It even works. I rebuilt the 5hp24 in my 2001 740iL.
I took my time and rebuilt it over many weekend over the summer. Wasn't in a hurry as it really is our winter driver.
It has 155k miles on it, it really did not need a rebuild. The only symptom was a little bit of a shutter sometimes when shifting into second gear.
I took the tranny apart, and found essentially no wear. The clutches looked fine, no torn seals, and even the reverse plunger had no chunks taken out of it as seen on other posts.
It's actually an easy job, taking the tranny out, and putting it back in is the difficult part.
Took my time, rebuilt a group/drum pack at a time, lined up the clutches, and it all snapped back together. I only replaced all the seals and clutches, that's it. I did not even open up the valve body. I figured I could always do that from under the car without having to pull the tranny.
Here's a slideshow. The slideshow came out weird, you have to go backwards to see the forward progression. Oh well.
http://bimmernut.com/5hp24show/