There's been a, uh, semi-civil discussion over at netscape.public.mozilla.ui regarding the very issues you all are talking about. The arguments have been over (A) the look and feel of the current UI and (B) whether native-looking widgets should be used.
There was a seperate argument (C) over whether or not ACTUAL native OS widgets (as opposed to XUL "look-alikes") should be used, and the decision was essentially that the current technology makes it too unfeasable/hard. In other words "if you want it, write it."
Regarding (A) and (B), there are a number of people who like the current UI. Others, such as myself, believe that it's crucial for the browser to look like it belongs in the OS it's running. That is, normal people want a native-y looking UI with familiar scrollbars, etc.
The issue of native-looking vs. "cross-platform" has lead to a lot of, uh, tension.
Anyway, lots of alternate skin, widgets and modifications have been proposed by various people.
In my opinion, the best alternative to the "official" theme/skin started about three months ago when Jeff Campbell came up with a photoshopped "mock up" of what he saw as being a better skin. It's at (LINK) . Much discussion followed. Then around christmas, Pete Collins began hacking together a theme that made it work. (see (LINK) and get the code at (LINK) in gz and (LINK) in a zip)
More recently, Pete has been working on a set of native-looking scrollbars (for MacOS, GTK and Win 95). The latest version is available here: (LINK) and directions for using it are here: (LINK)
It's still being worked on.
Ben Goodger is also working on a new theme (at least I think it's new) called the "conservative" theme) which will NOT be using Pete's scrollbars.
Anyway, it's confusing, but I invite everyone to join the newsgroup (NNTP server: news.mozilla.org, group: netscape.public.mozilla.ui) and contribute if you can.
(Hope I haven't stepped on any toes here. If I've said anything incorrect, I'm sure someone will jump on my ass with a correction.)
W