Well, RPM's would be directly affected by wheel size, yes? I have 255/40/17's which put the diameter at about 29. According to that handy calculator linked above, I should be revving around 3025 at 75 MPH with that size tire and 3.00:1 gears...
That calculator shows you what rpm your driveshaft spins. It doesn't take gearbox gear ratios into account, so it can't tell you what engine rpm is, although running in a 1:1 gear, the rpm it gives you is also engine rpm.
EDIT: Here is an excel sheet I made up, change values in the blue boxes only. If you're skilled enough, you can convert it to mph, or just do it on the fly. It shows you engine rpm for every gear, for any wheel height, tyre width, aspect ratio, at one km speed intervals.
You'll need to save the .txt file and rename it to .xls
I'd say go with the aod, I have 4.30 gears and an aod with a 3500 lock up stall converter and turn about 2600 at 65 and 3000 at 70-75 not sure with but an aod with a 3.00 gear would be like idleing down the road, also at last check I got 17 Miles per Gallon not getting in it at all