Print drums have been made clear up to 40X60 print size, though the largest I use is for 30X40.
The paper sticks pretty well to the walls of a smooth drum, so I wouldn't be too worried about collapse. But there are a few other tricks you can do to assist this. The nice thing about drums is that you can do either color or b&w work. But with very large b&w work more frequently inkjet these days, I wonder how much longer large rolls of fiber based silver paper will even be available. I notice Harman no longer offers Fineprint VC but only Multigrade IV (not my favorite choice).