> Is there any way to research the meaning of cultural references
> found in old piano rolls?

Usenet groups and mailing lists like this one are good bets.  We
discuss rather similar topics at the Old Time Radio Digest mailing
list, http://www.oldradio.net.

The great days of network radio overlap somewhat those of mechanical
musical instruments, so there's quite a bit to be learned there about
the culture of the 1920's through 1950's.  In fact, that's the major
reason I'm a subscriber to that list: fascinating stuff.

Mark Kinsler