Standard data forensics procedure is to write-protect any storage device which contains evidence, copy it bit-for-bit, and do all the decrypting and data analysis from the copy. The 10-try limit may protect your data from a random thief who lifts your phone, but the only way it's going to protect you from the government or any other technically-capable hacker is if Apple baked the limit into the flash memory-reading hardware.
And there's always this.
You can put a complex password on your iPhone:
1) Settings->Passcode, enter your 4 digit passcode.
2) Flip the "Simple Passcode" switch.
3) Set your new arbitrary length complex password.
4) Enable the "Erase Data" setting which wipes the device after 10 incorrect password inputs.
5) Enjoy entering your complex password every time you want to access the phone.
The encryption on these iDevices and the Macs is non trivial to crack. Combine this encryption with a properly strong password and that wipe feature and even the Police would be shit out of luck. I know of a case where a guy resolutely refused to provide police with the password and crypto-key for his MacBook. The cops shipped the laptop to Cupertino who sent it back after a few weeks having failed to crack the drive encryption. The cracking would take longer than the expected lifespan of the universe. Your only hope of getting into a properly password protected and encrypted device be it an iDevice, an Android device or a Windows phone is if there happens to be some software vulnerability that enables you to bypass the login screen.