I added the ability to also have comboxes, checkboxes or radiobuttons to choose from where you usually would use Ext.MessageBox.prompt.
The additional functions are
Calling them is easy as you would do it the usual way with .prompt. Just add 2 Parameters: scope and a configObject (according to the desired widget: comboconfig for promptcombox like you would pass to a combobox, radiogroup config for promptradio and checkboxgroup-config for promptcheckbox.
Find a zip attached with a full working demo file (drop it where ext-all-debug.js resides) and a diff for ext-all-debug.js (3.4.0). As Ext.Messagebox.prompt could not be overriden the usual way you need to modify the library.
i could upload patched versions of ext-all and ext-all-debug , but i am not sure, if that is allowed by sencha