2 related questions:
Is it possible to create an item type containing fields with checkboxes as the input type (i.e. "check all that apply")?
Is it possible to use those checkboxes in the Contribution plugin (similar to how that plugin will pick up controlled vocabs for creating dropdown choices)?
For the first, I'm not sure the controlled vocab plugin might get close.
For the second, the updated version of the Contribution plugin for Omeka 2.x moves those user questions into the User Profiles plugin, which does include checkbox, select, and radiobutton options. We're testing the upgrade path, and have high hopes that it'll be ready soon.