As bhayden pointed out, Sergei has done this in his Argosy Comtemporization
linked above. He dealt very effectively with the weight issue by "hogging out" large sections of the particle board and then lining with thin aluminum sheets to make them appear "whole" from the inside. This effectively turned the large cabinet panels into frames, not so far from what Airstream does with their custom cabinetry. The design is excellent.
He has not traveled very much with these cabinets, so time will tell whether they are durable enough for a travel trailer application. It might end up depending on your chosen type of travel-- if you're sticking mostly to freeways then perhaps it's fine, while if you tend to travel washboard roads, well then perhaps not so much. But the washboard roads are tough on the factory original cabinetry as well, so I'm not so sure it's a fair measure for durability.
Personally, I have rebuilt all of my cabinets from scratch, using pine framing and thin, light and flexible but strong plywood, to make my cabinets even lighter and stronger than the ones Airstream originally installed.
I'm no cabinet maker, just a desk-job hack who enjoys woodworking. But not everyone is as handy as I am, and the Ikea cabinets might be a reasonable solution for people who simply can't build the cabinets themselves, and can't afford to hire a professional cabinet maker to do it for them.
Some food for thought anyway...