Roland VariOS by Jsepeta
The Roland VariOS was a disappointment for me. At the time it came out, there were a few software tools that could do the pitch transformation it did (Acid, Live), and since you'd want to use it with a monitor anyway, you may as well do everything "in the box". Maybe it was just a sign of bad timing, I guess.
However, VariOS was a cool idea which was never fully implemented: as a sharp-looking 1U DSP engine for softsynths, Roland could have taken it somewhere. Mine was bundled with a 303 and a Jupiter emulation that sounded good, and I purchased the VSC1 (D-50 on a ROM card) with great hopes that Roland would develop more cards - perhaps a space echo or JP-8080. Well at least the vocoder function of the JP-8080 was released on the VSC2 card - they're now extremely rare and sell for around $500 on eBay. Makes me think that Roland could sell a few more if they had made them. I kept the VSC1 and use it in my V-Synth.
Sadly, Roland dropped the ball; if Roland had guts, they could have developed a competitor to the UAD Apollo or Muse Receptor. Instead it withered on vine.