Thanks for all the feedback. I see that my rationale was COMPLETELY wrong with the larger drum diameter. I actually thought I would be increasing resistance, but obviously I took physics way too many years ago. Makes sense now.
Maybe I just abandon the whole idea and buy a set. I was just looking for an excuse to reinvent the wheel, and I guess maybe buying a set of rollers and turning them into free motion would be time better spent.
Anyone want to try and give me a reason to continue on the solid maple roller quest? As far as balanced construction goes, these wooden drums would be very well balanced, and it seems like they would act more like flywheels themselves than the aluminum versions. I'm quite sure they would be heavier (even at 4.5") but is this a benefit?