Hi,
I tried to add similar extra edit buttons to these found on wikipedia (they add 10 more to the default 11 found on mediawiki). I've found that it is performed by javascript ( http://en.wikipedia.org/wiki/User:MarkS/Extra_edit_buttons). I tried to install it on my wiki as well (just had to change some details with location of images), but I wasn't able.
I'm using MW 1.6.7. Can it cause problems? What changes to code are needed to have it working?
Regards, Aretai