I imagine that you may have already seen this but, a quick search on the
Internet brings up this link:

    http://www.wiscasset.net/artcraft/issue11.htm

At least from what this page says, the Visuola was more of a concept
than an actual product.  It was to be marketed to schools and
universities but it apparently was never actually sold and quite
possibly never even made it to the prototype stage.

Also MMD 2002.04.17 give a brief description of the Visuola and a link
to the same page.

There is a book (or perhaps more of a brochure; it's not clear) that
talks about the Visuola, for $25.00 at:

    http://www.rarebook.com/bostbookjp/27243731.htm

The description reads: "Blazing A New Trail In Piano Playing."  The
Visuola Corp., 1927.  8vo., red paper wraps, cord bound.  A very good
copy of this promotional brochure for the "Visuola," a mechanical aid to
piano instruction.

The Visuola sounds like it would have been a very interesting device and
probably quite collectable for the right person, the same way the
Fotoplayer is for some people.  Too bad the Aeolian company didn't come
up with the Visuola earlier, so it would have had more time to market
the product before the Great Depression killed everything in the
mechanical music industry.

Douglas Henderson of Artcraft Music Rolls wrote the MMD posting and the
web page link.  Since he seems to have almost the only useful link for
Visuola on the Internet (I tried 5 different search engines) perhaps he
might have more information.  His email address is on his web site,
toward the bottom, at:

    http://www.wiscasset.net/artcraft/

There are many interesting pictures about mechanical music on his page
as well, fun stuff to look at.

Hope that helps,
Ray Finch