I'm wondering how would you micro step it lower then the half step option. If you want a simple driver look at this one.
http://www.p5taylor.btinternet.co.uk/19.pdf. From one chip mentioned only a 1/4 is being used. If you make a 2 or 4 axis driver on one board you don't have to get an other.:-) I was thinking about doing it but gave up on it since I couldn't figure out how to micro step it. :-(
Yoram