A client has a corporate, multi-level hierarchical content
classification/taxonomy scheme that want to use to classify documents in a
SharePoint document library.

I'm considering whether to recommend they develop a SharePoint custom field
type (msdn2.microsoft.com/en-us/library/ms446361.aspx) and a custom
field type control (msdn2.microsoft.com/en-us/library/bb417414.aspx)
to support UI, data storage, data display, validation, etc. for this
Classification column property in their document libraries.

Part of the validation that precedes the recommendation is making sure that
list column data created with custom field controls works properly
throughout Office 2007. Search is one of these areas (integration with the
Word property panel is another).

Questions

1. Are there any know issues indexing or search column data created with
SharePoint custom field type controls?

2. This custom column/control will most likely be derived from
SPFieldMultiColumn (i.e. it will be a multi-valued custom field type). Any
issues indexing and searching a multi-valued custom field type?