Dev has gone well, Ive been able to maximise code reuse without getting lost in abstraction. Theres a few other things I would like to implement like a "one click button user control" that uses javascript to disable the button after the first click and displays a throbber gif and perhaps even changes the button text to "Loading..." or "Please wait". Ill have to expose ValidationGroup, Text and the click event.
I still have a few issues with some of my user controls.
I have a UC which has a ModalPopup with login controls with validation. If I have multiple of these UC on the same page they fire each others validation which is not intended behaviour. Ive tried setting ValidationGroup to be unique (random generated string) on UC Init but still fires other instances validation. Will have to figure this one out soon.