TJ has offered you the best advise.

Other than going to 4x4 which is for sure your best bet there are a few things you would need to do to accomplish your other goals.

To fit the 33s ($700) you will need a body lift ($200).

To get the front up look you seem to want on your Frontier you could buy new upper control arms ($350) to give the front a 2.5" - 3" lift and add shackles ($50)in the rear to lift the back 1.5" This should leave your pick up with the front 1/2" - 1" higher than the back. While this will give you the look you seem to want, I do not recomend it. the Frontier and Xterra come with a nose down design to improve handeling.

The locker will require you to buy on-board air ($250) and an ARB Airlocker ($785). While this will help out quite a bit you will still not be doing any "hard lines." Aside from the traction issues which TJ mentioned you will also be missing another key component, a transfer case. Without 4x4 and low gears you will just be beating the hell out of your truck to try to do mid level stuff locked or not.

So the question becomes why spend over $2300 to end up with a truck that is less capable than a stock 4x4 Frontier. If you are commited to this truck I would take that $$$ and do a 4x4 conversion. It is a lot of work, but it would be cheaper and you would end up with a much better truck.

Here are a couple 4x4 conversions to look at.
Xterra 4x4 conversion
Only one Desert Runner 4x4