We've looked at this quite a number of times over the last couple of years, and it's rather more difficult than you might imagine. It's easy to imagine a kind of glissando type effect, but only at the expense of removing some other performance sensitivity - it's very hard to intuit 'intent' on the part of a player and doing so is very much not in the spirit of what the Eigenharp is about - we're trying to give the articulation back to players, not take it away. The one nice way we have thought about is having a strip controller mode where a note can be picked up and moved along the keyboard without having a new note start. This is also more complicated than it seems (or we would already have implemented it) due to the variable geometry of the Keygroups. Not such an issue on the Pico right now (though it will become more so in the future) but a real one on the Alpha. We'll keep on thinking about this though - it would add another dimension to playing.
I do believe that there is a parameter in the Scaler that limits pitch change rate - this may well give you the effect you are looking for on a monophonic instrument. Won't work with MIDI though, or AU/VST's, as they don't have sufficient pitch resolution in pitchbend to make this nice. I'll ask Sam to look at this and post to let you know.
That said, when we put the fingering behaviour into the Scaler then this (being monophonic) is certainly a more accessible idea, in the same way that partially opening holes on a wind instrument can allow one to slide notes while retaining expressive control over the process. I have the feeling it might be a bit of a trick to get good at though.
Of course, you can always turn the key pitchbend range right up. An octave or so will get you where you want to be, although I can tell you that the experience of trying to play in tune at that range is quite something... I'll buy the first person that manages that trick a beer, it defeated me!
John