Ground Zero Iridium speakers are very good choice for smaller budget. They offer very good price/quality ratio. Coaxials and separate systems are offered with normal and shallow mounting depth.
10 cm / 4″ Flat 2-Way Coax Speaker
extra flat only 30 mm / 1.18″
4 ohm, 50 / 90 W, 80 Hz – 20 KHz
Coated paper cone, Resonance free steel basket
13 mm / 0.51 Mylar tweeter