To give you a better idea of what i have in mind, I'm attaching a mock-up. Tell me what you think of it.
Something similar to that was actually my original plan. Unfortunately it goes entirely illegible on Windows (which is 16x16 without turning on accessibility stuff that makes _everything_ huge). I've been trying my best to avoid seperate code paths. Eventually I think I can detect the size of the system tray and use a nicer badge if it's above a certain minimum size. I don't think it'd take too long, but 'pretty' is generally not too high on my to-do list until all the functionality I want is done.
I've added a 16px mock-up. Hope this gets a higher priority. I'll send you the icons, in case you wish to use them.
On the first one, can you generate 3 plain green badges (no numbers, and no icon, on a transparent background), for 1, 2, and 3 digits, sized and positioned for a 64x64 icon? i.e. a 64x64 sized png that, if I placed it over a 64x64 icon, would look right?
I could, but it will be messed up when scaled down. Why do you even need a 64px icons. I would advise you to use 24px and 16px depending on panel size, imho that's the only way to get a crisp looking icon, although it will require some changes in the code. Think it over.
While I may be willing to special-case 16 and 24 as they're quite common, panel size can be anything on most Linux environments (32 isn't particularly rare, nor is 28), and since, as I said, making things pretty is not as important to me as functionality at the moment, it makes sense to use a large icon and scale down, as it looks better than using a small icon and scaling up. If you'd like to post the same thing in 24x24 (blank badges, 0123456789 in the font on a transparent background), it'll get used, but I'll definitely need 64x64 as well for the generalized solution.