I've never heard of doing this, but, there's a lot of things I've never heard of.
I can see, through my cloudy, Saturday morning, one-cupa, minds eye, several problems with doing what you describe and with finding the components.
From the little, very little, I know of the actual manufacturing process of rimfire ammunition, I would think that after the primed case is produced that there is very little left to do in an automated manufacturing process in getting a finished rimfire cartridge. The folks who have the machinery set up to make primed cases are likely to be the same folks who are manufacturing finished rimfire ammo (presumably, currently as fast as they can). I doubt that they would dump off a coupla thousand primed cases for the one guy in the country who wants to hand load them.
The second major problem I see with hand loading rimfire ammo is that traditional hand loading makes heavy use of the rim on a cartridge to accomplish the various tasks of the process. Crimping, striking, bending, mashing, stripping, or otherwise compromising the rim could result in, at best a cartridge that wont fire, and at worst, one that fires way too soon.
The third and last issue is cost. I have looked at many, many reloading equipment catalogs and other such publications and although I certainly may have missed it, I do not recall ever seeing any equipment to accomplish hand loading a rimfire cartridge. Now, it may be there, I don't remember seeing it. If it is there I'd imagine it is in the cost prohibitive range of expenses (for me anyway).
If you had the equipment, the components, the time, and got lucky, and after you paid shipping on all of that, you could probably load 22 lr for about $5 a pop.
This is just my 2 cents, which is what it probably costs manufacturers to make a round of 22 lr. Right now it's not what they sell them for.