Service Provider List

1 3D Printing

http://i.materialise.com - 3D printing service, also does stainless steel, alumide and titanium printing. Located in Leuven, Belgium

http://www.ponoko.com - plastic and steel 3d printing, aluminum plate cutting service provider in the USA

http://www.shapeways.com - plastic (from 1.40$/cm³), aluminum (from 1.75$/cm³) and steel (from 8$/cm³) 3d printing service provider in the USA

http://www.4d-solution.com - SLS 3D printing: plastic, alumide, etc. in Germany

From SatNOGS:

3d Printing at a Fab Lab or your local hackerspace: If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

T Slot - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. (Here's one in the United Kingdom.)

2 PCB related

Also take a look at this far more comprehensive list: http://www.opencircuits.com/PCB_Manufacturers

http://oshpark.com/

By far the cheapest way to get PCBs for prototypes in low volume, takes some time though (2 and 4 layers only), no assembly service

http://www.oshstencils.com/

By far the cheapest way to get PCB stencils in low volume

https://aisler.net

Similar to OSHPark but Made in Germany, also offers components and stencils (no assembly though), limited to two-layer boards currently (4 layer in Beta)

http://www.leiton.de/

Affordable PCB manufacturing (2-14 layers) in Germany

Also creates SMD stencils for just a bit more than 100€

http://www.multi-circuit-boards.eu/

Affordable PCB manufacturing (2-28 layers) in Germany

steel SMD stencils for much less than 100€ (smaller sizes even for 35€)

http://www.sunstone.com

USA based PCB manufacturer, said to be very fast and reliable, not the cheapest

http://www.ginzinger.com/cms/

PCB assembly/testing in Austria

http://wedirekt.de

PCB manufacturing in Germany