Kate your friend may well be able to make you one, the main problem would be fabricating the angles at the front. I am not sure what you would use, 14 gauge steel maybe and something similar in Aluminum plate. If you have someone that has access to it carbon fiber would be ideal, buying one made from the stuff would be prohibitive but if you can make your own maybe not.
Here is a link to the dieselgeek site so you can get some idea of what they look like off the car.
Panzer Skid Plates by www.dieselgeek.com
On the 1.8t's the plate has to come off to change the oil filter. You and your friend build a plate where that isn't necessary and you may have a very marketable item.
Dirt buildup is no more than you have with the plastic pieces.
I say pieces because dieselgeek now has what he calls "The Full Metal Jacket" which has two aluminum pieces to replace the plastic side panels also.
Sometimes you can also find a used one on VW Vortex or in the classifieds on this site.