2 sets of bunk beds?

Look for a Newmar Allstar 3950. It was made for a few years around '08 and '09.
Mid engine design allows for the master bedroom to be where the engine usually is in a diesel pusher. Has a bedroom for kids above the master bedroom. They also made a touhauler version that would work for you if you installed bunks in the garage.
Spartan chassis mid engine, low CG. 400hp. lots of good points. Poor engine access for maint.
most likely a bit noisy. Didn't sell well so discountinued

Check out the Thor Outlaw toy hauler. It does not have bunks but it has a large space for hauling things and it is has a queen bed for that space. I would think it would be easy to install two sets of bunk beds in that area. Two by fours with lag bolts and ply wood bottoms can create so great beds and anchoring to wall should be easy. You can build them to fit the size you think you will need. Then memory foam mattress trimmed to fit. The main living area has a queen size loft that is really quite neat. Then you can have a separate tv area with another bed option from couch and dinette in front area with another couch if needed for sleeping. That toy hauler space has some options that might just fit your needs. I love the idea of a bunk room for the kids. You could even do triples if needed for kids. Good luck.

I hope someone knows of a class a with double bunks, I have only seen class a with a single bunch and it was behind bi-fold like a closet. you will find what you are looking for in a tt or 5er, have seen many different models with all the features you are looking for.