An interesting article in the LA Times, discussing the architectural designs of mosques in America and England. He references a lot of architects and I've posted links to some of their works. In doing so, I came across a site called ArchNet, which features Islamic architecture around the world.
Zlatko Ugljen - White Mosque in Bosnia
Paolo Portoghesi (co-designed with Sami Mousawi) - Mosque of Rome
Ali Mangera - Abbey Mills Mosque (new architects have since been commissioned)
Islamic Society Boston Cultural Center Picture 2