Im trying to use the same sort of look to my menus on my RPG Im doing. Im hoping to eventually have it skinable but thats beside the point.
What you want is an image of your box at its smallest and divide it up into 9 sections.
So you have :
upper corner left, upper middle , upper corner right
middle left , middle middle, middle right
bottom left , bottom middle, bottom right.
With these 9 tiles you can make menu and character chat boxes of any size or length you need. Then just right your menu/chat/info over the top of the box. If you make a function that you can just enter the size you want and where you want it (FNCffmenubox(x,y,length,width)) it will make the job easyer too.
But..... Nothing beats sitting down with a pad of paper and working it all out before hand where its all going to go.
Have fun with the box idea and PM/mail if I havent explained it properly. (Was going to put a sample bmp on the end of this but they dont support that here. LOL )