I love the way Arqade (and various other SE sites) embraces its theme of gaming into it's site theme and logo. Do we want to follow the same steps and propose a theme?
Not the time for that yet, I'm afraid. We're still in beta, and likely to be for a while, until the site matures and the greater powers that are decide we're ready for prime time. ;)
It wouldn't make much sense creating a new custom design for each site that made it to beta; it's a lot of work and creative thought put into each website's individual design on Stack Exchange, and it would be a terrible waste of human resources, if the site turns out it doesn't meet criteria to be considered mature and worth keeping, and its contents later hosted on other existing Stack Exchange sites, on a per question basis.
We still have a lot to do to reach that level of self-sustainability, really. Currently, we're not at that point yet, and I don't think anyone expected us to be. You can track our progress on our Area 51 page, but so far, even the stats there don't yet display what we need to work more on, and which criteria have we already satisfied. It's too early, and most of it would be lighted with red warning messages, if it did.
I expect us to reach most milestones within a few months time, but it will involve a lot of work to get there, and it will depend on efforts of all of us. Our first objective should now be defining our scope in detail, and promote our website to the wider audience.
Sorry to disappoint you, but I do hope my answer becomes obsolete as fast as possible.