"What is the difference between the AODE and the 4R70W?
Mainly the gear ratios and the extension housing bushing and seal diameter."
I know they both have integral bell housings, I guess all you need to do is find one with the right bolt pattern and find\make the right drive shaft.
However: "Which transmission is better, the AOD or the AODE?
The AOD was a good transmission in it's day, but the newer AODE and 4R70W have many improvements. The AODE has a thicker, simpler, and much more reliable valve body that is much less likely to warp than the thinner more complex AOD valve body. The AODEs also all came with the 2 inch wide overdrive band and an A (largest Diameter) Overdrive servo. The input shaft is also much stronger on the AODE than the AOD. Lastly, the AODE has a lockup converter clutch rather than a mechanical, gear dependent lockup. What this means is that with the AODE you can have 2nd, 3rd, or 4th gear locked or unlocked. No longer do you have to decide between streetability and performance. You can have your lockup for efficiency, and unlock the converter for better acceleration. The 4R70W offers all of the above benefits with the addition of a lower first and second gear ratio to help initial acceleration. Beginning in 1998, the 4R70W also has the Mechanical Diode intermediate one way clutch, and an even better direct input shaft. Certain models also have hardened gears, such as the 1998 and later 5.4 trucks."
Got this from: AODE and 4R70W Transmission FAQs - Baumann Electronic Controls, LLC
They might be able to answer quite a few of your questions. They talk about a similar swap but from a 5.0 to a 4.2, not sure of the different bolt patterns.