6G Nano?

I am wondering if any of you have experience with/think that it would be possible to have a 6G (Eclipse) SW tank (FOWLR) with only one (maybe 2) fish (eg: small clown, small goby, something along those lines.) I wouldn't be using the factory filtration (I would upgrade to something else) or lighting (again, would be ready to try to upgrade - though I am not planning on growing corals or anything like that.) I understand that often tiny tanks are much less forgiving in terms of water parameters and such, but otherwise, any ideas?

Hrm ... do you think that a single percula clown would be too large for the tank? My LFS has very limited SW selection ... there are a few small gobies though I would prefer a single "centerpiece" type fish.

Well I'm not really looking to support anything other than the fish, so corals etc aren't really a huge concern. Because going that extra step means I have to mod the lighting etc, which I'm not really ready for. Though, it's always something I can do down the road if I decide to.

Now I've sort of seen some mixed things when it comes to filtration etc on a small tank. I am obviously prepared to be doing weekly small water changes. For this sortof set up, however, I plan on having a filter that will provide adequate surface agitation, capacity for beneficial bacteria to survive (media), and the ability to filter particulate matter (so basically, your plain old HOB or something like that ... now will this be adequate? Or do I need to look into protein skimmers and that sort of thing?

Yeah no rush ... I'm just playing with the idea at this point.