You could use the standard TAN Two Stroke chassis, or a 5F2A (Fender Princeton) style chassis from Mojo, Weber, Hoffman or others. Mod the stock chassis by moving the tube sockets to the top of the chassis, next to the transformers and you should be good to go. Check out the “Building a 2 Stroke Head” topic. It would be similar to this layout, except the chassis would mount on the bottom of the cabinet (similar to a Marshall or TrainWreck) instead of hanging from the top so the text would be right reading.
The hardest part of building a 2Stroke head using a screened, stainless steel or chrome chassis is drilling hole in the much harder chassis material. It’s do-able, I’ve done it with both steel and aluminum, steel takes longer and is harder on your tools.