200e

I think that something that is sorely lacking in the Neo-Buchla is 
voltage processors that allow you to do fine scaling/inverting.
The 210e and 256e give you this, but the scaling is stepped due to the 
digital nature of the modules.
I recently came across a potential solution for this: Sound Transform 
Systems, makers of the banana-compatible Serge, are now making "M-
class" modules, i.e. half panel-sized modules that contain 2-3 stock 
Serge modules which (will) span the complete catalog. These guys are 
actually the same height as the Buchla ones (4-U), but are the width of 
two Buchlas (like the 227e or 250e) and require a different PS, but 
they are almost completely compatible (I say "almost" because the 
pulses are only +5 V, whereas the 281e needs at least +10 V).

Of course, an even better solution would be if our pals at Buchla came 
up with their own, totally-analog version of these oh, so necessary 
utility modules (hint, hint, guys!). After all, not everybody is 
interested in presets!!

Otherwise, the Buchla is an amazing system, and every modular synth 
geek should try it out!!