Remove the min 4 character username and blogname on signup

I have a wpmu setup where users signup for new blogs. It seems wordpress has a hardcoded limit for min 4 characters in blogname and username i ms-functions.php i have tried to change it to 1, then the error disapers but the signup form just reloads and no blog is created. I also tried this plugin without any luck:

http://wordpress.org/extend/plugins/wpmu-blog-name-restrictions-override/

I run wp 3.4.1 and buddypress 1.5.4 (cannot upgrade buddypress because of some modifications i did to bp and the bd theme).

Anyone know how to workaround this issue ?