Thanks for the explanation.
I'll continue with the UI preferences using the current CobblerWeb. The core functionality is in the remote XMLRPC and can be reused.
I was also thinking that adding more information about the item fields is required. For example the header, default width of a column, output format, url format, action-function (e.g. for add/delete/rename).
Peter
I think adding settings to control output format is a Bad Thing. You should not have your code care about the output format. Any customization to the user interface should be controlled via CSS.
As for adding methods to the objects to tell the display code what fields are available (and type, list of options, etc), is a Good Thing, and what mpdehaan outlined is exactly what I was going to propose.