What do digic 4 and digic 5 even mean? It's not like we have geekbench to test these against each other. What an odd thing to argue over.The idea that at new 5D Mark 3 would not have the new Digic 5 chip and rather have two Digic 4's is not likely.
That a non-1d body would have DIGIC-V first is more unlikely.
Who says that Canon has to use all of the Digic-5 features in a non-1d body?
There is a geek benchmark test, it is run at dpreview.com.