I've seen (but never heard) Rogers swivo-era kits with a snare, tom and ride cymbal all mounted on the bass drum. I've also seen Rogers bass drums with a tom (or two), a ride and a full size crash mounted on them. Personally, I love the look of these setups, and I imagine it never hurts to have fewer stands to lug around, if you're gigging.
But again, I actually haven't heard any Rogers kits with more than a single tom and cymbal mounted on the bass drum, so I'm curious how much you all think is too much for the bass drum to take before it starts affecting the sound in a meaningful way. I realize this is completely subjective, but maybe there's something relatively close to a consensus out there?
My guess would be, (simply because you see far more of these set ups than others), anything beyond a tom and a cymbal, (or two toms and no cymbal), starts to get dicey, but that's admittedly an uneducated guess.
Another question: For those of you who mount a cymbal on the floor tom using a knobby mount, do you notice if it affects the sound of the floor tom?