Who needs a tool belt or an apron when you can just store stuff in your boots? 

Heres the original article the picture is from. There's a bunch of other fake stuff so probably not a real product. Although, the bread gloves might come in handy if you're hungry (just don't wear them in the rain).

There is some company out there that makes a gun holster that clips onto the top of the shaft of the boot. 

The main problem with this, is:

1.  The gun resides on the inside of the boot.  So you need really skinny calves.
2.  You need to be able to pull your pant leg up higher than the top of the boot to access it. You are talking about pulling your pant leg up 12 or more inches.  Not practical.

Most holsters deny you access when seated, especially if you are belted in while in your car.  So an ankle holster is good for that scenario.

If you can forego the boot, there are ankle holsters that can accommodate magazines, wallets, etc.  it can easily carry a folding knife.  But be aware of the local laws.

NY allows a 4” blade to be concealed, neighboring Connecticut allows just 3-1/2” last I checked.