If any of you are on Astromech.net, they have a section discussing all the particulars of how to build BB-8.There's also quite a few close-up photos from Celebration that show great details on the BB-8 static model.
Regarding the panels:
Based on the above photo with the access ports and interior frame, it looks like it might be a sphere-in-a-sphere concept, where there's a smooth inner diameter that separates the outer diameter by a few centimeters.
TinyP and Nussbaumer over at Astromech.net have drafted up a 3D print of the panels with this concept, and it seems pretty like a solid idea:
This would make a lot of sense, since each of the circular panels has lights on them, and having some thickness to each panel would allow LEDs and batteries to be recessed into them. Because of it's modular nature, and all the panels having the same thickness as the inner frame, it would give the entire interior a smooth surface on which the Sphero-based drive system could operate smoothly, yet allow the operator to access the inside to make any repairs or changes.
Also, in case you're wondering, Kresty, Savage, and Themodelmaker have nailed down the order and orientation of the circular panels. I've borrowed Themodelmakers graphics and oriented them in the correct fashion:
As far as BB-8's sizing goes, there's a good post in one of the Chrome Trooper threads:
I have dubt on Gwendoline Christie's Character.
Let me explaine.
On this picture we can see the tall size of toys:
View attachment 470354
So we know the size of Characters Toy
and we know the size tall of the actors...
So I make a table.
Blue = Known values
Green = Defined values
Red = Calculated Values
| Name | tall size (cm) | tall size (ft,in) | ratio | toy tall @100% | toy tall @104% | ratio 2 | characters name |
| John Boyega | 175 | 5' 9" | 0,837 | 146,4 | 152,3 | 0,870 | Finn |
| Daisy Ridley | 170 | 5' 7" | 0,843 | 143,3 | 149 | 0,876 | Rey |
| Peter Mayhew | 218 | 7' 2" | 0,894 | 195 | 202,8 | 0,930 | Chewbacca |
| 67,02 | 2' 2" | 0,84 | 56,3 | 58,6 | | BB8 |
| 191,31 | 6' 3" | 0,84 | 160,7 | 167,1 | | Kylo Ren |
| Gwendoline Christie | 191 | 6' 3" | | | | | |
Online modifiable table
What did you think about it ?
A good case was made that since the designers/creators are British, that the measurement of the bodysphere is probably 50cm/500mm. That seems in line with most of the measurements we've all come up with, but definitely makes more sense for the designers to use the metric system, and if we're going to use the metric system, I'll go out on a limb and say that I think the head diameter is probably 30cm/300mm, with the head height being 15-17cm (since it's basically half a sphere with a small lip at the base). Based on the table above (and assuming the toys are in correct scale), then BB-8 being about 67cm tall jives with the body/head measurements.
What do you guys think?
Its amazing how this little droid has captured the hearts and our imagination just as R2D2 did back in 1977 and we haven't even seen him in the movie yet! 
