Yeap! Holder is in the middle! That would be the challenge, but seems to be a nice idea. Just get the socket with spring kind retainer and match the hole on holder! Get the cut of course done on bezel! And maybe a rubber gasket between holder and bezel to seal it! Some white paint on inner side of holder too.

Something like this?

http://www.oemsurplus911.com/automotive/lightsockets/8524.htm

( I guess holder is able to get grounded when assembling on body )

You could even add a refractor filter in the middle of lense to disperse the bulb spot light on lense, like 72 and later got