I have built an instruments window that acts as a patch editor for my Proteus 2.
I made myself a window with 20 or so instruments, going all the way across the screen. I then used sysex strings to assign the faders and pan knobs to various parameters, like primary/secondary tone volume, the envelope parameters for each tone, and LFO amounts and rates. This, folks, has been incredibly handy! I've had this Proteus for years but I've never done that much patch editing on it, because using the single-knob, 2-line LCD menu interface was so painful. Yeah, I could have bought a commercial editor, but most of my other synths are things that have good panel interfaces (like the JD-800) and I hated to buy something just for this one unit.
However, this new instruments window has made a great difference. One of the most positive things has been having the time and level parameters for all of the envelope generators. I've never been able to "visualize" the envelope parameters in my mind just from reading the numeric values off of the LCD, but with the values represented graphically in faders, setting up the envelopes becomes a snap. Having most of the other parameters in the window means that I generally only have to use the LCD interface for choosing the sample sources; I spend a lot less time flipping pages and things go a lot faster. I can do nearly everything at the computer; tweak a parameter and click notes in the visual keyboard to see what the changes sound like. Very neat.
I labeled each instrument fader with a title that describes what the fader and (if it's set up) the pan knob actually controls. I arranged them in the order I wanted, closed most of the other windows, and then saved this as a "song". Every time I want to edit on the Proteus, I open the patch editor "song", do some editing, save the changes by dumping the patch data back to Metro (one track for each new patch), and saving the "song". Then, I can copy the sysex data, close this file, open the actual song I want to use the patch in, and paste the sysex data in to set up the Proteus for the song.