Could you not make the list as a datasheet, and then add filtering options to a set of textboxes? (I don't really know Access 2007 and whats added in that, so maybe there is an easier way)
Im not sure if this limit your seing in your valuelist can be worked around within the valuelist, or if the correct choice is to use a datasheet, or convert your list back to being SQL based, and solve the locking issue.
With what I understand your need to be:
1) The ability to view and filter several records
2) The ability to select a single record, and view further details about that in a SEPERATE form
With my knowledge of Access 2003, I think you should be using a datasheet type form, instead of a listbox, unless there are some fancy new features in 2007 for listboxes.