I haven't done sigs in a very long time (Used to make them for a different game, it was my source of premium-currency income).
But this is what I've done in a rush.

The problem with transparency is this:
- You either save as GIF and the quality sucks big time
- You either save as PNG but the size of the file increases a lot
Edit: couldn't find the same fonts, so I used what I had on my PC