Dragnet does currently have a "My Open for all projects" page.
If you go to the "Server Home" page, the menu links (Query, Open, My Open) on that page are for "All Projects". To view your open items for all projects click "My Open" from the Server Home page. The view all open items in all projects click the Open link from that page. To query across all projects, click the Query link from that page.
Along those same lines a report showing all open, grouped by assignee, across all projects would be nice to have for a weekly manpower meeting we have.
You could do this by using the Query all projects form to query for open items and order the query by assignee. Or you could just click the "open" link from the Server Home page then click the "Assignee" table header to order the results by assignee.
Or are you talking about grouping by assignee similar to the way Dragnet groups by milestone? If so, I can add a feature request.