Hi, I haven't done this. Wanted to suggest that you make sure you can get the mattress into the RV before you go out and buy one. The reason RV manufacturers use the ones that they do is because they can be folded in half to get them into the unit.
If you are referring to a "Sleep Number" mattress that manufacturer makes them specifically for RV's. They are extremely expensive however most love them, I personally am not a fan. The only complaints I hear about them is that they are electric and require an electric outlet close to the bed and that when changing altitude or going into a different climate (colder) they deflate. The diaphragms are also subject to punctures to which there are also numerous complaints.
I actually prefer a good memory foam/gel mattress. I find them to be more comfortable and about half the cost. the memory foam will conform to your body and the gel will regulate your body temp.
We have a Sleep Number bed at home and love it. However in the TT we have the regular mattress with a foam topper. Couldn't justify the cost in my mind to put a Sleep Number in the TT. BTW, the Sleep Number mattress is basically an air mattress with solid support framing around the perimeter. It comes in pieces and has to be assembled in the camper. It normally comes with a metal frame that sits on the floor. If you have a raised platform now, it may need to be modified or removed.
Take me in. I recently bought a sleep number bed from www.reecoupons.com/view/nest-bedding. It can easily fit into my camper. It is really comfortable and not so much expensive. I also recommend you to try getting it, i am sure you will also like it.
Had one in our previous 5TH wheel, only issue was change in elevation you will need to adjust the pressure up or down. Ever notice your unopened snack bags at higher elevations? Kind of puffed up. Wasn't a problem, just adjusted accordingly. Happy Campin....