Hi,
I posted some of what I do with a Printrbot Metal Plus here : http://3dprintboard.com/forumdisplay...rintrbot-Forum

It has an autolevelling feature that is very useful and the volume you are looking for. Also, the new metal hot ends are available and it's a realtively simple install : http://printrbot.com/shop/metal-ubis-hot-end-2/