I didn't see this mentioned elsewhere, so thought I'd post it. Sorry if it's a duplicate. Feel free to delete if it's redundant.
Sony A7R teardown at LensRentals
"The completely disassembled Sony A7R consists of about a dozen major pieces, held together with 29 screws of just three different sizes. A typical DSLR has around 120 screws of 11 different sizes."