you mean making listboxes, combo boxes and such? editing the gui xml? Sadly, there is no program around to make this easier. though much of it is documented on the lavishsoft wiki, i would imagine that it is a bear to learn if you have never messed with that kind of thing before.
Every time i make a GUI for my scripts, i think to myself "I really should write a C# program to make this easier" Then i just forget it and make what i need to make by hand. I think we all do that. The other trick you might be missing is, look at the EQ2 scripts they have. They have a lot since most of the powers that be, play that game and they have a lot of sample stuff to work with. Might help learning some of the stuff