The Coopersonic Fader pedal had two knobs, for fade in time and fade out time, along with a switch to trigger the fades. The knobs allowed you to set independent fade times of up to 40 seconds; it wasn’t stereo though. This would make a great simple utility pedal plugin. I know you can simulate this to an extent with CV slew/AR Gens and a pair of VCAs, but the Slew/EnvGen plugins don’t seem to allow such long times; a readybuilt plugin would be a better solution. Usage scenario: placed post looping pedal I could trigger a loop fade out, and later bring the loop back with another triggered fade in. Dropping the feedback setting on the LP3 wouldn’t quite achieve this as I presume the loop would decay and completely disappear? I haven’t got a Mod Dwarf yet so I can’t confirm this behaviour 
Another use would be to fade out synth drones while I played over the top. Fades times of up to 60 seconds would be good. https://www.musicradar.com/reviews/guitars/coopersonic-fader-575037
as for the “not stereo” issue, you can just use 2 plugins in parallel and trigger them at the same time with the control to CV plugin. As for the 60 second fade time, that sounds like something you’d either have to modify on the plugin, or develop the feature.
Actually, you don’t even have to use 2 plugins, you can just connect the same plugin to both outputs.
Yeah, that would work, but wouldn’t that sum the stereo out to mono, unless I’ve mistunderstood? I’m sure I’ll find a solution once I’ve got my hands on a Dwarf.
well, you’d get a copy of the same thing in each ear. The outputs are independent.
I think it can be achived with multiple Slew Rate Limiter - MOD Audio, no ?
If you have :
Control to CV - MOD Audio (that would be your ON/OFF fader trigger)
→ CV to a 10s Slew Rate Limiter
→ CV to a 10s Slew Rate Limiter
→ the CV finally controls the knob of a Volume 2x2 - MOD Audio
You should have at least 20s, but maybe 100s (not sure if the values multiply or add) long fade.
Thanks @Rom, that’s the first bit of info I’ve seen which confirms the Slew maximum time. 10 secs is useful and I could probably place a few in series or add one after an envelope gen. Incidentally, I’ve had much fun with a similar idea on iOS, in the AUM plugin mixer. A very nice chap wrote a script at my request, to use in the midi utility plugin Mosaic. It simply slewed any CC changes over a user set time. I hit a footswitch and it sent a CC value of 128 to the channel fader, but instead of going from 0 to 128 in the blink of an eye, it slewed the CC value change by up to 60 seconds. That idea could also work on the Mod Dwarf I think?
The best thing about making it with CV plugins is that you can make this for any potentiometer in any effect ! So no need for the developers to implement this in every knobs of every plugins : with simple tools you can build very complex behaviours !
Of course ! You can even make a single footswitch send CV to different Slew Rate Limiter and make different timings for 2 of 3 knobs… And since CV plugins don’t consume much CPU you can have a lot of them in your pedalboards
Today I’m learning about slew rates 
Great info guys, thanks for the input.
I’m using this set up but the slew rate limiter only seems to fade the volume2x2 to half for me. I’m sure I’m doing something wrong here, but is there are way to have this set up fade the volume 2x2 to zero?
during the adressing, on the advanced settings change the CV mode from bipolar (-5 to 5) to unipolar+ (0 to 10)
Advanced settings… of course. DOH!