Need a more robust Multilist...

I need a multilist style widget but I would like to put more than just text into the fields. For example, I would like to have a two column multi list, with one column being plain text, and the second column containing editable text fields, or perhaps even individual button widgets. In other words, I want the fields in the multilist to act as containers for other widgets (editable text, buttons, ect...).

I have glanced at the current Multilist implementation, but I am unsure if I would be able to just modify it, or am I going to need to create a custom widget plugin from scratch (are there any tutorials/wikis for creating widgets/plugins?).

Thanks