Really does no one consider the possibility of making the GUI a web application that runs in browser on the users own machine? It would be like running an instawallet on your own computer with the possibility of entering in console commands.
The issue there is the blockchain; in order to do anything, or show the user anything, the web application needs a trusted copy of the blockchain. If it's a locally-running app, most users don't have a database program running on their local machine for a web app to hook into. As a public website that users can visit (like instawallet, or blockchain.info's wallet) that's very doable (the server also connects to the P2P network and trusts its own database records for users to query), and I mentioned that as something I'm looking into, using node, like the bitcoinjs project.