Is it possible to create a Custom Field Type of "Issue" ?

Hi,

I would like a custom field type that lists all the existing issues in a combo box, of which I can select one. Much like the "Project Picker" custom field type.
Maybe even have it in a cascading combo box style (first combo box = Projects, second combo box = Issues).

i know you can Link Issues, but that's not really what I want.
Would it be possible to add this in a future release of JIRA?

Many thanks, kind regards,
Eric