Yeh, I'm on Void 2 as well, and buttonless. And I have 5 button mouse. XD
I've often wanted to make my own FF Theme, but had no idea how to, or whether I could be bothered if it was a huge task. I wish they could make it easy like Samurize or something.
Go to C:\Program Files\Mozilla Firefox\chrome and unpack classic.jar with WinRAR. Now you can edit the images you need and a lot of other stuff too by editing the css files. Once you are done, open the classic.jar file again and drag the edited files in at the right location. One thing that sometimes comes in handy is using Photoshop to find out the colour number of text etc. you want to change and then search the themes directories for files containing that specific number. (Containing text)
You can skin firefox by just editing userchrome.css. If you're using 2.0, get chromedit plus and check out some examples. Otherwise, you'll have to create the file in your profile dir. It's best to work with the classic theme, as others will have padding and margins you can't get rid of, etc.. The best one for this IMO is "cute classic." Also, the custombuttons extension will replace all your buttons..
I do use userChrome (I actually have ChromEdit Plus too. XD), but I know very little CSS, and none of which could help, I just add little scripts I often stumble on. Thanks though. =)
I wish there's a software to help skin firefox themes though, just a simple photoshop plugin or something would be awesome. (or maybe winamp, I hate pixel-placement-coding)
Thomax: Do you know how to open the jar file? (e.g. its a zip file, unzip it.) Go to the directory "browser", and then open toolbar.png up. edit as needed.
Also, some of the other toolbar buttons are in different image files. (I haven't organized everything yet, since I can't seem to make a good cut button)
to vkeios: i edited the toolbar.png pic and saved over the orignal file and i alost edited the other pngs that needed to be edited, but nothing has changed. The buttons are still black