The Pearl Avenue brance of the San Jose Public Library combines PV cells and art glass in a vertical application. It is noted in the January issue of USGlass magazine. Also see www.glass-art-peters.com

Sunways, which i believe is a german company, makes multi colored polycrystalline photo cells though im not a huge fan of the way they look...

Thin film PVs typically are a dark brown/black color. Most PV cells cost about the same per watt but output varies. So if you want maximum power, you're limited to silicon. If you have lots of space or don't really care about wringing the last volt out of sunshine, then thin film panels can fit your needs.

before sticking PV cells on the roof, place a solar thermal water collector - best bang for your euro in solar energy. Also insulate, insulate, insulate.

Yeah, what tk said. Solar thermal and a good envelope are where it's at.

Also - I'm betting they're going to be dark, no matter what color they are, if you want efficiency. Dark colors absorb more light.

This company makes pure solid black PV's, as opposed to the standard blue speckely color:
http://www.sunpowercorp.com/

make your own with raspberries and pomegranates:

http://www.solideas.com/solrcell/english.html

color ones most likely produce less efficient than blue/black since PV cell respond differently based on the wavelength of lighting spectrum.
I saw one presentation by solar associates that showed PV with different colors, however he said the efficiency is much lower than blue/black.

Solar cells respond differently to the different wavelengths, or colors, of light. For example, crystalline silicon can use the entire visible spectrum, plus some part of the infrared spectrum. But energy in part of the infrared spectrum, as well as longer-wavelength radiation, is too low to produce current flow. Higher-energy radiation can produce current flow, but much of this energy is likewise not usable. In summary, light that is too high or low in energy is not usable by a cell to produce electricity. Rather, it is transformed into heat.

http://www1.eere.energy.gov/solar/pv_cell_light.html

Thanks to all for the help.
I didn't find the time to reply before. Sunways was the firm I was looking for I think, since a friend told me about a german company that was doing it but he couldn't remember the name.
I have had several warnings about the problem of efficiency of lighter colors than the regular one. Since we have a rather small surface to cover, I guess we will probably go for the regular one anyway.
I'll keep everyone updated if you guys are interested... And I'll post an image of the house later to show you.

please do

there you go