Oh, sigs are easy to make! They can be simple yet still look very good. Take mine for instance. All I did was take the image used for the
UO login screen (at the time, only the one the 3D users saw...I'm a 2D player and had to open up InsideUO to get at it), crop out the section I liked using PaintShopPro (the old, old Windows 3.1 version), and inserted text using the color I wanted and a shadowing effect. Sounds complicated..but it super easy.
Use Google Images search for finding good backgrounds, or in-game screen captures. Scan something you like out of a book or a magazine.
You don't even need special programs! Many good sigs have been made using Windows Paint.
You can also post in a thread such as this one asking for someone to make you a sig. Many
UO forum users enjoy making sigs for others. Just include what you'd like to be in it in general..any text..anything special...