This is becoming a more popular FR than I would have imagined, initially.  It’s been cropping up from time to time with more frequency now.

In the meantime, here are a few other options that really work:

• Morningstar MC-x versions (over MIDI)
  EHX 8 Step Program (via expression)
  Disaster Area MIDI Baby / 3 / etc, (creative CC sequencing)
  Source Audio Reflex (rare, but over MIDI or expression)
  Lexicon MPX-1 (as a MIDI generator – rackmount – my “best kept secret”)

There are other boutique options, but these are some of what I use all the time.