Not as an expert, but cabinets I have seen in RVs are made with lighter weight material than home cabinets, such as using double-wall hollow panels, and lighter weight woods. If you have a local cabinet maker in your area, might be a good idea to go and discuss what you need with them. Many pre-fab cabinets for home use are made with manufactured wood panels, which are a lot heavier than plywood panels and shelves. Of course, with any light-weight material, you may have to give up a bit in overall strength, so consider that need vs. the weight thing.