Btw, Arpeggiator has that hold function
When people were making Step sequencers, I decided to use the granular stretch to make a clip sequencer.
Basically, I had Arpeggiator on hold, and a Random device alternating between 4 different notes. Each note would hold a different synced sample, the fourth one was none. They also each sent back different velocities (to give color feedback to the controller). What you were able to do then was have a sequence of like 6 Green, one Yellow and then one Red, one bar each of loops. Silly songs like that. Sorry to hijack
But applying it more to the sound design opportunities, I imagine you could once again use Arpeggiator except as a pitch mod on the sample.
And to get More crazy, exted the duration of the arp to 101%, and have Sampler set to 1 note Legato mode. Yum. I'll have to get back in the lab now!!