We went to the RV Supershow in Tampa yesterday and all the 5th wheels we looked at had the island in the kitchen. We think that takes up too much floor space.
I built an island for our 5ver. and it is on casters. Basically what it was 2 upper kitchen cabinets.....18"wide that I put together. They were the right height I wanted along with the 2" swivel casters. When we move...I roll it to the back of the 5ver behind where the lv slide comes in. Lock the casters and it has not moved. We keep our plates/glasses/bowls and lot of extra stuff in that "island".