Thought I's share the results of a project to create more usable space within my Airstream, a 2013 27FB. A friend of mine did the project first on his 2007 27FB and the cabinet dimensions were exactly the same.
The trailer came with cabinet doors that pull down onto the floor, giving access to a storage space at floor level, shown in the photo below. These spaces are generally shallow and difficult to find productive use.
There's a lot of empty space behind there than can be recovered. Here's a new slide out drawer.
Side view.
Across the hall, under the stove is another shallow floor level space. Since the wheel well is directly under the stove the drawers can only be so deep, yet I was able to make them about 30% bigger than the prior space just be taking advantage of some dead unused space. One additional advantage I didn't realize until the project was complete is the ergonomics of access. Grabbing the handle and pulling straight out verses dropping onto the floor, plus its much easier to get things in a drawer than bending down and peering inside the old space.
I'd say this is a moderately difficult job. Depends on your own handyman skills. The drawer faces are the same parts, just re-used, and screwed to a new wooden box. Ball bearing drawer slides are readily available. It helps, as I did, to have a friend with expert carpenter skills to make the boxes for me.