I found a 1933 Duo-Art in a Mason & Risch piano on eBay (item
3736927193) and I do not ever remember hearing of such an animal.
Here are my musings about it:

I think this is may be a very rare piano.  Mason & Risch was not
related to Mason & Hamlin.  They were known for their Vocalion reed
organs.  Their relation with Aeolian was from when they sold Aeolian
Vocalions and Aeolian put players into them and sold them as Aeolian
Orchestrelles.

I suspect this piano was a specialty and not a production model.
Perhaps it was specially made for the president of Mason and Risch.
What do you folks think?

D.L. Bullock    St. Louis
www.thepianoworld.com

 [ In 980605 MMDigest Jim Heyworth described a similar piano
 [ offered for sale in Western Canada.  -- Robbie