Is this, by any chance, possible: editing or changing the drive icons (in the small drives bar), maybe making them have a slighty different colour? What also woul be nice, as an alternative, if separator bars could be placed between drives.
You can edit the icons for different drives the same way as for Windows/Explorer.
Or you could use individual Go buttons for each drive, instead of the Go DRIVEBUTTONS command which makes the list of drives, so that you have full control over their icons, labels, separators, etc.
(If you just want separators between types of drives, not between drives of the same type, you can do that by using the drive-type arguments to the Go DRIVEBUTTONS command.)
I can´t locate those small icons, like in the screenshot, so i could change two of them, like in the example.
I´d like to keep using the automatic Go DRIVEBUTTONS, but may it´s possible to still use that & change those two icon drives anyway. Maybe they´re part of the *.dis files. I downloaded the package HDD_Letter_Icons_v2.zip, but they only contain the large icons, which i currently don´t use.
The icons in the zip should contain various sizes in each .ico file.
Yeah, i found that in the meantime, but somehow it looks, as if the large icons are shown, & i also can´t open it in my graphic prog. In Irfanview the Icon look different again. Basically, it´s those small icons like in the screenshot, i want to change. I could change the look in windows paint, but can´t save it as .ico & keep the transparency. Is there a simple way of changing some colours & save that, any small freeware tool?
Hmm, all this is quite confusing. First, i don´t know, where the actual icons are. I have the set from the zip, which i try to edit. There is a character, like "r" above the icons. The ones i use in Opus are almost the same, but the charakters are under the icon signs & seem to be added by windows rather than being contained in the icons (there are no examples of icons with drive letters under the icon). Also, when i edit the icon, which i think is the correct one (16*16, 256) & save it, the wohle file goes from 80 kb to under 10 kb.
The icons that the drive buttons toolbar displays by default are the drives' actual icons; they're the same icons you'll see in My Computer (both in Opus & Explorer). I think they come from shell32.dll but I'm not 100% sure about that these days. Opus just asks the system "what's the icon for this drive?", the same way it asks for icons for folders and files.
The letters displayed in your screengrab above aren't in the actual icon, they're simply the textual label for the button.
The icons in Leo's .dis file (or any other .dis file, for that matter) are nothing whatsoever to do with the default icons the Drives toolbar displays.
My zip file isn't a .dis file (not sure where that idea came from in this thread); it's a zip with normal .ico icon files along with instructions on how to tell Windows to use them in place of the default drive icons so they appear in the Opus Drive Buttons list (as well as My Computer, etc.).
Thanks to you both! Looks a bit complicated. I tried, what Leo hinted, two drive button bars, both using "-CDE" style parameters, making a pseudo separator between them.
It's not very complicated. You just create a .ico file and then set one value in the registry to assign it to the drive.
(Of course, if you've never used an icon editor before there is a bit of a learning/reading curve.)
I yet have to experiment with that icon editor & the icon changer program. Like is said is solved it with 2 drivebars. If you havem for example, the drives C, D, E, F & G, & want a separator between the CDE & the FG group, the first drive bar would use "-FG", the second group "-CDE", that would look live C D E | F G.
I also want to add, that the different icons were only an idea, how to make different drives looking distinctive, which is also achieved by that trick. This would be maybe an idea, a new parameter for including separators in a solid drive bar?! 
I don't see how a new parameter for separators in the drive-button lists would help. Anybody who could find and use that parameter would also be able to add the separators the way you have, which isn't really any extra work (and keeps things simple).
By the way, if you've copied the entire drives toolbar then that is overkill. You can put a second copy of the drives button next to the original one on the same toolbar.
Well, it looks good, anyway. I uses the "drive buttons" thing, which i thought is a toolbar. I think, in one single drive button, you can´t insert a separator, without using this trick.
Here is, how it looks:
Cool. That looks right. Looks like that's all on a single toolbar, consisting of (I presume) three "drive buttons" buttons.
(*I wish there was a good word to describe buttons that turn into lists of buttons. 
"Button generators," or something.)