So basically I want a slider bar inside my message box. Much like when your choosing what your character looks like.

Slider needs to be associated with numbers starting at 0 ending at 50. Letting the player slide through those numbers to pick one.

Thanks for the help

I don't think that's possible.

is there any way to get input from the player inside a message box?

You can add the numbers as options, then script using buttonpressed to find out which one they selected. That's really all you can do.

what about when selling items, if you have more than 5 or something you get the slider with numbers to choose from? Isn't this scripted?

It's hard coded into the interface AFAIK.

UI elements like that are done in Flash. You could edit the existing menus with a flash editor, but I don't think there are any functions to call a new UI element.

these menus are in the interface.bsa file ?

Complied flash menus, yes. You'll have a hard time de-compiling them and editing them to your liking however. And even then, adding new UI elements isn't really possible right now.

For all intents and purposes, what you're trying to do can't be done unfortunately.