It's always a treat to see the mechanical puffers!
In addition to the 400 & 401 puffers, Marx also made a 490 mechanical puffer:
The 400 mechanical puffers are the most common by far, and can be found in at least two variations, with stamped steel drivers and with 17 spoke diecast drivers. The 490 and 401 puffers are harder to find, although I would say the 490 version is the most scarce of all.
Here is the "smoke" that came with the 490 mechanical puffer:
I love the Marx mechanical puffers, but they are one type of locomotive in my windup collection that I rarely run. I just don't want to take the chance of damaging the fragile rubber bulbs... 
I do have a 401 puffer with a regular riser gear motor - it was a parts loco that I repowered. So, when I get the urge to run a puffer, I just put it on the track instead... 
