Adaptative (to user's role) edition of objects with many "properties"

Hi there, for applications sometimes the user want to edit an object that has many instvars to edit or it's composed. I guess that this could lead to forms too large to be practical for the end user's daily use. One solution to this is could be the partition of the form into smaller forms with tabs. The problem is that one should describe once and let the description prepared to be capable of build several composed forms to each model. This could be archieved by different form building policies. A concrete form build's policy should define the look of the component. To give a simple example of this policy: if the component to build is no bigger than 6 "fields" it should be like "the normal ones" (actual default) but if it has more than 6 "fields", put the first 6 in a tab and the next 6 in another tab (or more, until the total ammount of fields are reached). The policies should be extensible but generic enough to maintain economy in the design. Is also desirable collaboration with user's role to gain additional customization of the observation. A smarter policy could take advantage of grouping info set in the descriptions. As an example some fields could belong to the #'admin.indetification' or #'operator.identification' group/role to keep grouped the right fields of the editor's form for the object/model. I'd like to hear opinions about this or to know about better approachs to solve this problem. cheers, Sebastian Sastre PD: as a side note I'm evaluating to use Magritte with Glorp mapping (like Ramon Leon suggest) so, if I'm undesrtanding this right, the descriptions to map the persistance of the model objects should be "like" another role observating them but describing the persistance wanted.