I realize with shame that it has been over a month since I last posted here. This is in stark contrast to how productive I've been on Sinciput itself.
The user interface on Sinciput has seen considerable improvement, and all of the main classes of content have been stubbed out now. Current SVN code boasts support for queries against the US Library of Congress.
While not checked in yet, the version I've got running in Eclipse here now makes use of jQuery and TinyMCE to add rich "Web 2.0" capabilities to the front end.