I think you can create an input box with litdev. It is just a form with a textbox and 2 buttons. But I din't try it.
I also advice you to take a look at Small Visual Basic, which is the next generation of small basic with an enhanced compiler and a form designer, which you can easily us to crate any dialog you need. You can also reuse apps created with sVB as libraries as explained in the instructions in the ReadMe file. This exactly how the Dialogs library is created, which you can use directly to show an input box like this:
value = Dialogs.InputBox("Enter any number:")
Note that you can change the design of this input box by modifying the Dialogs project source code in the sVB\samples
folder.