I am looking for the the German Manufacturer of plastic covercaps (a german
speaking/language search specialist may help).  The plastic caps fit 8
millimeter diameter holes and cap is 13 m.m. diameter across tops. 
They come in many colors like white, black, ivory, brown, etc.  An
example of the cap is featured on on a website in England at
http://www.protak.co.uk/Products/ffprodShelfCap.htm .  The manufacturer in
Germany also make larger ones to fit 10 and 12 m.m. holes.  The
caps are slightly curved on top and side walls have slight ridges to
help fit.  They are commonly used in cabinets, furniture, window
frames and doors to cover screw holes.  I would imagine the
manufacturer sells these parts for about US$0.01 each in large volume.
 Thank you in advance.

Dear widgetman,

I managed to find the German manufacturer of those or identical covercaps:

INDEN GmbH
Dieselstr. 6
74223 Flein
Germany
--
Phone: +49-(0)7131-5862-0
Fax: +49-(0)7131-5862-22
E-Mail: info@inden-gmbh.de
Website: http://www.inden-gmbh.de/

The cover caps are available in numerous sizes, among them the
8mm/13mm variant you specified, as well as those for 10mm and 12mm
holes. The standard colors are black, white, silvergrey, mahogany and
beige; caps in other colors can be produced upon request.

As for the pricing: If you buy, for example, a quantity of 10,000
black 8mm/13mm caps, the price per 100 units will be 0.75 Euros
($0.96), so one single cap would cost EUR 0.0075 ($0.0096).

See their complete range of covercaps here:
http://www.inden-gmbh.de/html/produkte/inhalt_artikel_e.inc.php?id=048&arthaupt=3&artunter=1

Hope that this answers your question!
Best regards,
Scriptor

This looks like the item...thank you.