I think it would be easier to keep the two ends straight and concentric with a shaft that went all the way through.
I don't think weight is a concern, I was only suggesting a few extra rings, spaced apart, to keep the center, length wise, concentric with the shaft through the center. If you are building it like a sand flee or V-drum sander there isn't any pressure against the drum, Not sure about a thickness sander, I have no experience with one of those.
10ER #23430, 10ER #84609, 10ER #94987,two SS A-34 jigsaws for 10ER.
1959 Mark 5 #356595 Greenie, SS Magna Jointer, SS planer, SS bandsaw, SS scroll saw (gray), DC3300,