I've only been at it for a half year or so, but the most useful to me for this purpose has been my 4MS PEG (similar to a Make Noise Maths or a Befaco Rampage). Really anything that can create multiple and CV-controllable envelopes and slews I'd think would be useful for a kind of controlled chaos aspect, when used creatively.
The Hypster sounds pretty cool, wouldn't mind trying it myself......
A thing I've been experimenting with a bit in what may be a semi-related way has been the 4MS Percussion Interface w/ Expander. The name is kind of misleadingly narrow though. It converts an incoming audio signal into a realtime CV envelope, with a sensitivity/threshold setting, sustain/decay, an optional envelope follower switch, independent amp levels for both the envelope and an inverted copy of the envelope, and has a couple other little tricks up its sleeve to boot. When you think about that creatively it offers some really interesting possibilities. For example you could feed in audio from a TV or a radio or a pre-recorded field recording or whatever, fine tune the threshold and release to be either very liberal or very conservative, and thereby have a continual incoming stream of random little CV triggers and spikes and modulations, both positive and negative, to modulate whatever other sonic parameters in your system you wish. It also wasn't terribly expensive as I recall, I think under $200 with the expander included.