Hi
I think that you are missing the point of GPL.
Under GPL you are entitled to charge a fee for distributing the software. No-one says you can't make money.
You cannot prevent other people, once they have bought the software from you, from copying it and redistributing it for a fee.
The 'freedom' that the GPL talks about, is the 'freeness' of the source code. It guarantees that the source code must be available, and places a responsibility of a distributor to provide the source code, should the customer ask for it.
So under GPL you will be able to develop your own OS. If you build on existing GPL'ed code, you are obliged to publish your source code of the modified apps.
There is nothing to stop you writing proprietary apps from scratch for the OS, and using a proprietary licence for them. You are then not obliged to publish the source code for those apps. It would make distribution difficult though.
I would be hesitant to charge a big fee for copies of Linux. Implicit in any commercial transaction would be an expectation on the part of the user for support - something like "I've paid for this, and I'm entitled to expect support". You may end up endlessly fixing customer's installation problems for free.
I like the Canonical type licence = software for free, support for a fee. You don't need to waste energy policing copying and all that stuff, you support paying customers who sustain your business.
I like your attitude, but I think you need to come down to reality. Linus Torvalds was an honours student when he started Linux, who already knew all about C, structured programming and microprocessor architecture etc. etc. Also, his first post was about what he'd done, not what he was going to do.....
Development of the Linux kernel is taking place faster and faster. So it's getting bigger and the rate of change is increasing. Quite some competition!
Good Luck