I'm actually doing that myself. I was thinking of selling my Coleman and getting a larger Alpha Wolf, but after some thought about why we are looking for a larger trailer, I found it would be cheaper in the long run to just replace the jackknife sofa with a larger one.
The one in there now has 10" of arms, and it 66" wide. I found a 68" one without arms, that will fit in the space and just need to make a side and back panel for it. It will stick out about maybe 2 inches but the gains are huge, as in over a foot of space gained. Now 5 people can sleep comfortably and when weather is bad we can all sit facing the TV, 2 in the dinette and 3 on the sofa, where only 2 could sit on the sofa and the third had to sit on the bed. Two stones, one bird, thousands saved.