There are many of these constant voltage transformers available
surplus.  They were very popular for small computers a few years ago, but
have (wisely?) been replaced with MOV-only type surge protectors.  They
should be available very cheaply as compared to the original prices.  I
know of a 3 KVA, 110/220 volt model with 5% taps that is available for
about $100.  The thing weighs a ton (realistically about 225 pounds.)  If
anyone wants this tank it belongs to a friend in Northern California who
would love to get rid of it but doesn't want to move it around.  I think
it is called a Stabilitron by GE.

 [ Others were made by Sola and Topaz.  I believe Jody is using one of
 [ these units to protect his battery of computers, too! -- Robbie