Adding a slider?

Thanks for your responses! I, too, thought it odd until it was mentioned to me by my trailer repair person who was lifting the coach for us 4"- more clearance that was desperately needed. 1989 Prowler was in the age of low riders and we sometimes bottom out and have damaged the jacks underneath - so replaced those and lifted it to prevent this issue again. That was not expensive - only about $1000 for both. We are told all the time what a beauty she is - a real classic. I used to think the stares when we pulled into a campground was from being so old. I mean everyone else has these really great looking new fangled homes, and I admittedly was a little embarassed at my classic humble abode until someone walked up to us and said what a beauty she was...then I got proud and started thinking maybe people look because she is a good looking classic. :-) We paid $3000 for her and now appraised at $15k. Was a steal - bought it 4 yrs ago and had only been used 6 times, one owner, kept under cover since 1989 and still had the cabinet door plastic stickers & covering on them. Everything was in perfect condition including the tires of all things. I mean when Les Schwab says you don't need to replace them because they are in such good shape, that says a lot. :-) We did do some cosmetic upgrades to it (had to get rid of the mauve & some ugly wallpaper), but it is just in prime condition and we don't want to sell it (as much as I'd love a brand new fifth wheeler with all the perks of my home). I have looked into the porch addition (the attachable screen room), but when the RV guy told me that the business next to him does these slider additions, I started wondering. I read that folks are doing these on coaches, but was curious if anyone had done this on trailers. Thanks everyone!