I hope I'm wrong, but in this case it may be not so easy for ML as just unlocking these features. There may be quite a lot of code necessery to write, in order to make it running on 1Dx. It can even be not possible at all and until ML team takes in it their hands, no one except Canon knows it more or less sure.
I don't find it not ethical, what they admitted. It owuld be not ethical, if they would deny but someone would prove it.
If this is what they did was not ethical, then we live in a world, where everything is not ethical as well, or worse.
Windows Pro vs Windows Server - without one byte in register, different price.
Printers differing in one additional chip making them worse for purpose
Processors with bridged jumpers to force them work at specific speed
Ink cartridges with processors
Car engines operated with software not allowing optimized results
Producing another case and some buttons for commercial product and selling it for three times the price
Car parts requiring to be changed for no reason after the guarantee period is over
As far this business is more ethical than others, because here I haven't seen something like planned obsolescence (read more for explanation and other links:
http://en.wikipedia.org/wiki/Planned_obsolescence). In terms of ethics I will defend Canon in this case (not being a fanboy myself) because I have seen hundreds of really not ethical behaviors and this is not the one. Hiding this information would not be ethical, admitting it is ethical.