Final PWB thickness depends on your requirements.  I have built 16 layer
boards in .062 thick.  This could not have been done several years ago.  
There are many ways to skin a cat, the following is one example.  It is heavy
impedance high I/O product.  I have also done a double blind 16 layer (8 over
8) in .062 thick.  Today the tuff tuff stuff are those .093+ parts with the
.8mm pitch.
The following was pasted from an excel sheet and I deleted some verbage; the
final board met the .062+/-.007.  I would be able to do a layup for you but
cannot send enclosures via technet [which is a good thing].

Cheers,
Boston Brad


plating 0.0014 Diff Pairs = 100ohms differential
1 top 0.0006             .004 trace width
B 0.0040 .004 edge to edge
2 sig 0.0006             
Core 0.0030
3 GND      0.0006 Plane
B 0.0040
4 sig 0.0006             56.109 ohms .004 trace Diff Pair
Core 0.0030
5 sig 0.0006             56.109 ohms .004 trace
B 0.0040
6 GND 0.0006 PLANE
Core 0.0030
7 sig 0.0006             56.109 ohms .004 trace
) B 0.0040
8 sig      0.0006             56.109 ohms .004 trace
Core 0.0030
9 GND 0.0006       PLANE
B 0.0040
10 V3p3 0.0006 PLANE
Core 0.0030
11 sig 0.0006             56.109 ohms .004 trace
B 0.0040
12 sig      0.0006          56.109 ohms .004 trace
Core 0.0030
13 GND      0.0006 PLANE
B 0.0040
14 sig      0.0006             56.109 ohms .004 trace
Core 0.0030
15 sig 0.0006             56.109 ohms .004 trace
B 0.0040
B 0.0025
16 bottom 0.0006          78.776, 71.53 .008, .010
plating 0.0014
0.0679