As many guys I started with a Mendel90. My printer was bulit according nophead github files with some changes due to parts availability. If you print PLA all is fine but when starting with ABS or other stuff a very small smell of a wind can destroy your print. I looked on thingiverse and in several online resources but nothing was appropriate to cover the Dibond version. Ok, my printer frame is from 3mm aluminium sheets but there is no difference in general.

As I am not using any 300mm spool the customised holder is a bit smaller and we can use one of the holes of the origin holder for the covers. If you want to use the big ones please consider the spool holder to be app. 50mm higher. The enclosed holder is designed for a 12mm rod. Nonetheless I use it for an 8mm rod with a bearing spool holder. The filament guide rod was a 3/8" carbon tube from kiting. Please use whatever you find ;). The guide has been mounted backwards to ensure that the PTFE tubing is always running as a nice bow to the extruder.
The cover plates are made from corrugated cardbox material. Of course, you can use Dibond, Acrylic or something similar with 3mm thickness but cardbox is the cheapest.

The only parts which I designed are covers and the small end caps itself. The remaining parts are taken from the things mentioned under remix.

A suitable front housing with doors you can find here: http://www.thingiverse.com/thing:755654

Update 2017-03-22: As I was out for a longer time here now the last update. Some pictures will follow within next month.
Changes for V1.2: End cap now scaled correctly. As I have had issues with entangled filament I changed holding of the spools to a bearing supported version. Since then no problems anymore. The part spool holder was customised and will fit to many spools (may be all between 500g and 1kg).

Update 2015-04-06: Just did some small corrections on the cover plates due to copy-paste issues. -> V1.1