ApplescriptObjC [Output Box]
I believe this is what you want. Run the code in a Cocoa/AppleScript applet template in Script Editor and try it out.

set a to do shell script "echo monkey"
set window_rect to current application's NSMakeRect(40, 40, 500, 500)
set window_1 to current application's NSWindow's alloc's initWithContentRect:window_rect styleMask:15 backing:2 defer:false
set text_field to current application's NSTextField's new
text_field's setEditable:false
text_field's setDrawsBackground:false
text_field's setStringValue:a
window_1's setCollectionBehavior:(current application's NSWindowCollectionBehaviorFullScreenPrimary)
window_1's setContentView:text_field
window_1's setBackgroundColor:(current application's NSColor's blackColor)
window_1's makeKeyAndOrderFront:(current application's NSApp)