My modified SlikStik classic design fits everything you've mentioned: 2 8-ways (w/7 buttons), trackball, spinner, 1 4-way, 1 top-fire joystick, and as a bonus an asteriods layout.

(More pics available on my site.)
It's worked out pretty well -- the only minor problem is that the spinner is "cozy" with the 4-way and top-fire joysticks, but it actually isn't that much of a problem if I'm using a smaller knob, such as the Oscar MAME engraved knob or the SlikStik aluminum skirted knob.
Actually, if I had a chance to do it over, I'd move the trackball into the center of the panel. Other than that, I'm happy with the layout.
Kevin