Couldn't you use the arcade start buttons for the SNES and Genesis start buttons, and those middle buttons (coin buttons?) for select?
Hmm... never really though about that!   

  I imagine that would work just fine.
Were there any games using 8 buttons?  I can't really remember any.
I think I will go ahead and eliminate 2 of the buttons, and I can do just like you said, p1 for start and coin for select.  Cool, thanks!  
I am thinking strongly about incorporating an add on part to the front of the panel.  I could make some detachable "boxes" to go on front of the CP.  These would hold two of those mini racing wheels that fit on the spinners from groovygamegear.  I don't want a frankenpanel, so I think removable wheels would be the way I will go.  Plus, I want to get this up and running and the wheels are something I could always add later.  The idea of attaching extra modular boxes to the front could also really help with the games taking odd controls and such.
Also, I am really set on getting the 3 menu buttons off the cp to under the bezel.  I think I will put the player and coin buttons under the bezel too.  No use having extra crap on the cp.  This is a lot of fun.  Sort of like building a chopper, as in, how much can I remove from this and it still works.  Clean and bare bones is the name of the game!   

  Unfortunately I will be playing tons of games so I cant really get rid of the 7 button layout.  I could drop to 6 but I really love the Neogeo stuff so I won't get rid of the thumb button.
I am really set on the Joust theme now.  I probably only played Joust a dozen times on the arcade, but many many times on atari 2600.  I always liked the Joust concept and especially the side art.  It just has a real appeal to it.
I will try to get some other pics up tonight.