Opinion of 2x4 frame under full size SUV. Safe for towing still?

I have a Nissan Armada and I'm debating different techniques to get the body on the ground.

Option 1 is a traditional bodydrop. This would work well, but I really don't want to raise the floor.

Option 2 is to channel it. This would also work well, but I think I'd have to do about a 2.5" channel and I think it will make my floor look strange.

Option 3 is build replace the back 2/3's of the frame with 2x4 box tubing. I think this would work well, but I'm concerned about strength. I would still like to use this to tow a boat, car trailer, etc. Has anyone had any experience with a 2x4 frame under a large SUV or truck and still used it for towing?

I appreciate the input.

-Aaronwww.artofnoize.com

Aaron ask Max at Bio kustoms.i think duck and the boys at DIB used 3x3 on there dually but dont quote me on it.....Max has a forum on here called ask max..Ill be doing my expo soon and i had planned on using 2x4