Yes,
Java (Swing) does support pluggable-look-and-feels.
Javatoo contains a fair number of available ones (most are even free/open source). Googling a bit (or reading the documentation on some of those) will provide instructions on how to set it.
That said, How do you get less "basic" GUIs? My suggestions: use the GridBag layout as much as possible (Google for Grigbag Tutorial if you need to), and use an
IDE to design the GUIs. (NetBeans has a nice GUI builder, but
Jigloo is looking promising as a plug-in for Eclipse. I don't know about the GUI capabilities of other IDEs.)
These are my two cents.
Piscis Babelis est parvus, flavus, et hiridicus, et est probabiliter insolitissima raritas in toto mundo.