I have the external Eyetech `EZ-VGA Plus' Scandoubler/FF for my A1200 desktop. You have to bare in mind that when you have an external one it will protrude an extra 4" from the back and when it's made from sheet metal like the EZ VGA that could be a lot of strain on the video socket when dangling off an A4000t.
:-)
You could try getting/making a 23-pin video extender male-female but probably your best bet is the internal option.
Just out of curiosity, why don't you get yourself the wonderous Picasso-IV with it's superb internal Scandoubler/FF? It's the best there is since it supports full 24-bit unlike the 16-bit hacks...
