I did fancy employing a large amount of modeller's licence and using a CEP trailer to make a 3-car unit, as some class 207s were so configured for a while - eg http://www.semgonline.com/gallery/class207_2.html and also http://www.semgonline.com/gallery/class207_4.html
However these units were never anywhere close to being green in this configuration! I must say the extra coach made such a difference to the unit but I've not pursued it. Incidentally, the CEP's lighting circuit is slightly different as its interior lights only worked in one direction, but all the 2H's lights (headcode and interior) displayed correctly through the CEP trailer.