I don't know about 5.29s.  I would stay with the 4.88s personally.  I had 33 with stock gears and didn't like the loss in power.  I then regeared and stayed with 33 for a while, but gas mileage sucked even more on highways.  RPMs were bearable, but just seemed a little too high for me(maybe cause I was use to the stock gears and 33s).  I then switched to 35s and everything went back to normal.  Going up mild hills is no longer a fight for my tranny as it did when it had 33s and stock.  I don't have to have the ECT button on all the time anymore. 

Mileage wise,
I would get about 16-17 stock(heavy foot does that)
33x12.5s and stock gears I would get 13-14 (corrected)
33x12.5 and 4.88s I would get 12-13(corrected sometimes as low as 10-11 but then I started driving slower)
35x15.5 and 4.88s I now get 14-15(corrected but not having to watch how I drive)

You want real world experiance, that is as real world as you can get.  I don't drive my truck to much, but when I do I keep a close eye on the mileage and write it down to see what mods affect it more.  By going to 33x12.5 affected it more than adding the supercharger.  Regearing to proper matching gears helped a ton.  As far as power for towing is concerned, you'd be better off going with 4.88s with the 35s and getting a second set of 33 strickly for towing to help your engine and tranny when it needs it.  just my 2 cents.

OK, but same truck, same tires, same lift there is not going to be a big difference between 4.88's and 5.29's.  Only 200rpm at 75mph is not going to change much.  And around town it might help lug around all that rubber.  I'll take the extra gear, especially since  they tow with it.

In my 4runner I'm running 4.56's and 32's, soon to be 33's.  I'm at 3000rpm at 72mph and I still get 19mpg cruising at 3000-3200rpm, only a loss of 1mpg over stock gears, tires, and no lift.  I think I have a little too much gear right now, but the truck is happy cruising all day at 3000rpm.  It's a toyota.  I think 33's will be perfect and don't expect to loose any mpg.

The higher rpms don't really hurt mileage.  It's all that drag from the lift and tires.  And that automatic needs all the help it can get with that .70 overdrive and wide gear spacing.