Just received my black 32G Iphone 5 today, after running a few benchmarks and playing around with it I can confirm the actual processor speed is somewhere around 1.2GHZ. It appears that it may even have a scaling feature to clock up and down based off load as they have been seen on geek bench anywhere from 800MHz-1250MHz. Here is my geek bench result:
http://browser.primatelabs.com/geekbench2/1063323
http://browser.primatelabs.com/geekbench2/1063323