Need2know, other than the logos, you will have to do a lot more customisation to get phpnuke to reflect all your necessities.
These include (but not limited to): Topic Icons, User Icons, Smileys etc etc.
Means that you will be spending a lot of time on getting phpnuke to work and look the way you want it to. Before you indulge, may I suggest that you 'choose' between a number of nuke forks.
Postnuke is a fork of phpnuke and is a lot more stable and feature rich; myPHPnuke is another fork of phpnuke which in turn gave rise to Xoops (based on Object Oriented Programming).
phpnuke itself is born of Thatware... phpwebsite is also a phpnuke fork being developed by the Appalachian State University. its pretty good, but lacks a wide range of modules/addons. (did I forget the little geeklog
)
The point is that you have a choice; I have been following these nukes right from the beginning and my choice at the moment is Xoops. Its code is the cleanest and smartest, even security wise. phpnuke is the most popular one, abeit the most buggy.
So choose one for your live site and maybe you can experiment with others.
Good Luck!!