I'm not doing any specal costumization but the game's UI is motly just one big Canvas that the iso-view is drawn in and you can click on things like in Diablo. I'm useing normal scrollbar, buttons, entrys and messages.
I guess you could call it ugly but I like it.
I Don't know much about SDLperl I just happened to come across it shortly befor seeing the quetion and didn't see any one mestion it so thoght I would. I'm quite happy with perlTK so far so I'm sticking with it.