4.6 kg system carry solution

Hi. I want to have a better carry solution for my system: 1 camera and 3 lenses plus 1 flash. (details: D800E, 14-24G, 70-200 VRII, 35/1.4G, SB900)

I was using a Tamrac camera backpack and they all can fit in it. But it is barely fitted, very tight, and hurt my back.

I am asking you guy's experience on what carrying solution should work well. My primary usage would be traveling. e.g. going trip, hiking, walk around on the street, etc. And occasionally I need to shot in events.
I have a few ideas but I am not confident which one would works best:

1. Lowepro backpack

2. Lowepro belt system

3. Cotton Carrier that attached the camera to the chest

4. a small luggage specifically design for camera system. e.g. I heard one from Lowepro that can double as a luggage and a backpack at the same time. Also there's one from Thinktank for example.

And for each of them I have some doubts if it would works for me.
e.g.

1. backpack might hurt the back (like the Tamrac I am using. But I heard that Lowepro's design are better at letting the user few more comfortable).

2. belt system might make the equipments more easy to be hurt/damaged

3. attaching to the chest looks awfully awesome. And easy to scratch the camera too.

4. People might be more tempted to steal a luggage. I have thought of attaching a steel string from me, but that looks silly.

Any suggestions? Thanks so much in advance!