There is a physical limit on how thin we can carve the fromt to back. If it goes too thin, the truss rods will pop out of the back, making a very sad day. Usually, we are about .9 inch thick. We can shave it down to .8 safely, but keep in mind that the thinner the neck, the more reactive it will be to humidity changes since it will be less massive.  
 
I know not everyone is Stanley Clarke and Mark King, but these guys play with very narrow necks. I think it's because they are less fatiguing to play and with a shorter distance to travel between strings, it's faster to switch between them. Of course, misfires are more likely the closer the strings are.

And for the question that started the thread - yes Mike, the Excel has the comfort taper as stadard.

Mica, Thanks for your knowledge, insights, and suggestions! You are the best!!  As per our recently concluded conversation, I'll get the old calipers out and get busy! Call you next week (if not sooner!)
 
Thanxxx again, Mike..........
 
(Message edited by 5stringho on December 27, 2006)

Ok.  My proposed neck dimensions (on a five-string MK) for comment:  
 
Thickness: .9
Nut width: 1 7/8  (1.875)
24th fret: 2 7/8  (2.875)
 
This is pretty close to my 5-string Fender Jazz.  
 
I could probably live with a smaller 24th fret. Thoughts?

And, by the way, can anyone tell me what a standard MK 5-string with classic taper measures in nut, 24th and thickness?
 
Regards!

Mica,
 
I'm curious where that measurement (the 0.9 thickness) is taken since I'm assuming there's a bit of a taper.
 
Dave

Jim; according to the Alembic site, the classic taper on an MK Standard 5 string is 2.00 at the nut and 2.50 at the 24th fret.  The site doesn't list the thickness, but Mica's post above suggests 0.90.  For comparison, the comfort taper on a 5 string is 1.875 at the nut and 2.930 at the 24th fret.