Would be really cool if we were able to bring exposed filters (and pagination) in for options build from views. This could allow really flexible and powerful finders. There are a couple ways I've thought of and probably some more, but thought I'd get them down somewhere...

Popup widget
Have a rendered view of the current selection with a button that pops up allowing you to change the selection. This popup could have a view with checkboxes/radios and include pagination and any exposed filters. This fits with the way media module does with it's media browser (which includes a views based finder) which is a similar problem. The result is quite nice...

Field prefix/suffix on option_buttons widget
We could capture the exposed filters and pagination as part of the selection handler and put them in using field prefixes/suffixes. There will be a few things to solve around the forms/pagination (ajax etc), but it's a potential.

Directly output a view (widget)
We could directly output an entire view and have the style plugin append the checkbox/radio to the rows being outputted. This would probably end up similar to the popup except acting in-line.