There's room here for a dedicated site to focus on all the little design widgets that a developer needs too: Login boxes, modal dialogs, growl style notifications, mouseover effects etc. There's a lot of individual jQuery plugins available (and jQueryUI is too spartan), but for someone who is primarily a backend developer, it can be hard to put together something with a consistent look.
Although the lack of decent Dojo documentation should put you off. Unfortunately I don't get to make that choice and mostly have to guess / Firebug my way to a solution. Also, Dojo excels at reproducing a desktop-type app which might not be what you're after.
it can be hard to put together something with a consistent look
Totally, and that's why I go with a whole site theme and leave it there, definitely don't have the talent to go mixing and matching :)
I agree with you though, although I don't know if it would be something designers would use... but I really like the idea of going to a site, picking through different elements and combining them into something amazing. Any designers like to give us their opinion? :)