I asked the lady I was talking to a couple of weeks ago about the paint, she said that they do sell it, but only in large (probably quart-sized) cans.
I mentioned that I had the older white color, and asked if they had any, she said she didn't know if it was the same or what. So, she couldn't tell me if that paint they sell was for version I or II. That was kind of odd considering they are 'THE' people you go to for that. Don't get me started on the reason I called them in the first place, I can't understand how a large company like Canon doesn't know what they are doing, I had to go through hell before I finally got my order settled, it took me several calls to get it through their heads what I needed.
So, the only thing I can tell you is to search eBay, I know that a guy there 'used to' sell a smaller can of it, probably the older stuff, but still, he sold it, and I know it was mentioned (here?) that someone would buy the can and others would buy smaller containers of it. That way the cost wasn't crazy, plus, nobody can use all of the paint that comes in that large can that Canon sells, or sold, or...
This paint on their lenses is more than likely lacquer, (I don't know for sure though) if so, that can be matched at an auto paint place probably, that's how I would attack that. I know that all auto paint and body shops know how to match paints, but it depends on the type of paint. If it was an acrylic enamel it would be super easy, but I am pretty sure it's not.
As far as applying it, I would dab it on with a very small piece of sponge, really small, make dabbing motions until you get the coverage, then after it starts to dry I would 'pick the paint up' to give it that texture. What I mean it, like frosting, make the semi-wet paint have small bumps, so to speak. More than likely you could even use your fingertip after it starts getting to a point where you can get it to take some texture. The paint really needs to be built up because you can't do it they way they originally did it, it was probably laid on very thick with a large airbrush, but trying to match that thickness on a small area takes some skills, but I am sure it can be done.
I know how to do all of this, (I think) but I have not worked in that particular kind of paint, and if it is a lacquer it is very thin, so it means it'll have to (probably) have to be worked a lot differently. If it's a lacquer I don't think that other paint will stick very well, it's been years since I've messed with this stuff, but that's how I remember it. Lacquer 'may' stick to acrylic enamel though, but I wouldn't take my word, ask a paint shop, they know this stuff. Maybe someone that has painted similar stuff will see this and let you know.
Anyway, I hope this at least gives you an idea as to where to start.
Please let us know if you do find a place, I know that I could use a little bit myself, and I am sure that there is a bunch out there that would.
Randy