I have 45 blogs that run on the same Wordpress theme and all have the same plugins/funtions etc. The only difference is the content and each blog is hosted on it's own domain. It's becoming a pain to update all 45 when I want a small tweak doing, or adding an extra banner here and there. I think the best route is to transfer them onto Wordpress MU so that if I needed to chnage a banner, I can do once and is updated accordingly across all 45 blogs. If you are interested, please PM me what previous Wordpress MU experience you have, time frames and quote. Thanks!