Duplicator dual carriage and light, ABS redesign

Because original parts presents real weaknesses, I design these new carriage parts. I made these in ABS.
See pictures give a good idea of the making and installing process.
I have made also the heating bed arms, see at : http://www.thingiverse.com/thing:288308
I have made also X axis ends, see at : http://www.thingiverse.com/thing:288293