Doing dropdown menus has been done by bloggers to the Ocean Mist theme here, and also to the sandbox theme, but it takes a good understanding of CSS and experience. Whether you can do it with Vigilance or not, I don’t know and I’ve lost the links I had to the blogs where it has been done.
Indeed, I’m just thinking of switching to Inuit Types, it’s a great one! So I already created a thread to figure out how to add a header to it (guess it might be of interest to other bloggers, too). Another thing I would love to change is the fact that it only shows extracts, not whole posts on the mainpage. So I’m just in the process of deciding which theme to use, thanks for your replies.