An appealing art mural on porcelain tile might be just the ticket. Just find an artist (painter or photographer) whose work you like and who would license their work for this job. Send me a high res. digital file and I can make it happen. The installation would be enhanced by including some sort of frame (granite, tile molding, etc.) to set it apart from the surrounding stucco.

I would forget the rock. I'd choose something like this wood or vinyl siding. Siding color in the color of the grout (it appears a light gray). Keep all trim white as you have.

If you want some ideas on brick and stone combinations we can help. We've had people with this dilemma before so you're not alone. I've seen all types of combinations.

This is all stone and brick combinations.

http://www.flickr.com/photos/buechelstone/sets/72157626640764781/

http://www.flickr.com/photos/buechelstone/sets/72157626765407618/

Hello mate, find a plastering guy who applies ArcusStone lime plastering, looks like a combination of Italian stone and travertine tile but is much stronger. I do this however; I'm not in your area. You can go to Google or YouTube to see it. It's is what I would apply, if I were to change that beautiful brick finish. I am a 30 years plastering contractor, with over 250 videos on YouTube of how to apply plaster.
Best wishes.
Kirk Giordano plastering