Size: Whatever really. Just follow the limits. I won't even attempt to use something bigger in dimensions than 500x150, or bigger in filesize than 80kb. I'd also rather not have one any smaller than 300x100. But if someone actually posts something that's 250x75 that still kicks ass then meh.
Theme: Anything. I was looking for something along the lines of an interesting design or pattern. If I had to pick a theme it would be futuristic, but don't limit yourself because I'm open to just about anything.
Resources: Again, I don't have anything specific in mind. I was actually just hoping to see something original with nothing copy&pasted into it.
Colors: Nothing specific here either. Although if you can, I'd like my post wrapper color to be the border/in the border, so the scheme should be one that doesn't look to ugly next to it, but that's flexible too. My post wrapper color is #CBCFFF.
I can copy&paste things all by myself, I can fiddle with filters myself. I want something that I'd have no hope of ever doing by myself. If you aren't capable of that then don't feel bad because I can't do it either, but just don't post. If I was looking for some lame SA screenshot/something from google images with my name pasted on I'd do it myself. This is the only really important part, the sig and av must match, and if you use .png then I don't want transparency. I like transparency, I like .PNGs, but the idea that around 80% of the people who see my sig would be seeing it as being on a fugly white background just bothers me.
If I like it I'll add it to my rotator. If I really like it I might remove the rotator and use it exclusively. I know it might be both vague and asking a lot, so if none of the people skilled enough to do it bother, I'll understand. And thanks in advance to anyone who makes a serious attempt.