The RMI Rocksichord was a type of electric harpsichord & piano that had a very brief but important history. It's character was a nice balance between electronic and acoustic sounding instruments. I always thought it fit somewhere in between a rock and classic Broadway/Jazz styles and help blur the line between them. I notice it most in the original scores for Pippin and Company.
Sadly, there are few of these left, so composers aren't using it anymore. Even worse, Jonathan Tunick (one of my favorite orchestrators) now considers it an "obsolete" instrument and recommends replacing it in his arrangements with more contemporary instruments. In the concert version of Company at Live from Lincoln Center a few years back, they substituted the Rocksichord piano sound with a concert grand and entirely eliminated the iconic electric harpsichord from the score. In doing so, they removed the period flavor and, I think, lessened its impact.
As for the latest Pippin revival, I just hated what they did to the score. It sounded a bit like Wicked (another show where I loved the music but didn't much care for the orchestration). To be clear, I am referring to the Pippin original cast album, which was orchestrated differently than the original Broadway production (which I saw twice). The composer, Jonathan Schwartz, described the difference between the two as the live version being more "Broadway" and the album being more like what he heard in his head when he composed the music. The closest record of the theatrical version is the awful DVD made from a cable TV broadcast of the road show in Canada. It has a scaled back version of the pit orchestra (fewer musicians) in which they seem to have eliminated the strings entirely. But the Rocksichord is in evidence throughout, supplementing the acoustic piano and providing some very ethereal underscoring with its electric piano stops. Not quite like any other electric piano. Hard to find any equivalent.
Soniccouture made a Kontakt virtual instrument from the Rocksichord. Best of all, its free.
Though, unfortunately for me, it requires a later version of Kontakt than my system can run and I can't afford to update everything just for this. My system was custom built for me a decade ago and meant to be close to state-of-the-art back then. Updating would not only mean a significant expenditure, but updating all my VI's and scores and these days I just don't have the time, the funds, or the energy. So, I thought I post the link here for the benefit of those who do. (If anyone is still reading this forum.)