Ability to add "kerning" (tracking / padding) between all characters?

First of all, thanks for this great module! It's saved my butt a couple of times already.

I'm interested to see if there's any way Signwriter can output rendered text with increased tracking (a more familiar term might be "kerning," but that refers to spacing between two specific characters, rather than common spacing between all characters on a line). On a basic level, this could just be an option to add a certain number of pixels between each character as they're being rendered. Here are a couple "proofs of concept" from the comments on PHP's imagettftext function:

http://us.php.net/manual/en/function.imagettftext.php#60547
http://us.php.net/manual/en/function.imagettftext.php#74949

Is this possible within the scope of this module?