Art brainstorm

OK, dear reader, you are hereby appointed as member of my Brain Trust. You know, like the janitors on Scrubs.
So let's have a brainstorm.

In the nineties I made and sold quite a lot of paintings and drawings. I'd like to get back to that. And of course I want to use the Net instead of schlepping art around the county, that gets tired.

There are various options:

1. I could make digital art and sell it only electronically.
2. I could make digital art and sell prints, printed by myself or outsourced.
3. I could make physical paintings or drawings.

I don't think anybody yet has had success with selling digital fine art as digital files. I don't know, this would require a good plan and perhaps a twist. (By twist I mean, perhaps the art is a comic too, or illustrations to an ebook, or...)

If I outsource printing of digital art, I can't sign them. But they could be sold pretty cheap. Quality might be an issue.

On the other hand, I have a feeling that people who buy fine art mostly want originals, or at least something signed. But this introduces shipping. I have and could use UPS. This is a good option, but a bit expensive, and I have to be home for pickup and so on.
I could use the post office, but then I either have to use a lot of time on it, or use the local mail box, and that one won't even take an A4 (8x12") envelope without folding. And a 15cm by 20cm drawing is awfully small, donchathink? (Although actually, Duane Keiser is successful selling very tiny (like 3x4 inches) paintings. I could do it, but I'd prefer to also have a solution for A4 and A3 sizes.)

So what do you think? Lemme hear your ideas, good and bad, crazy and nuts, nuts and bolts, nuts and raisins, nuts and soup.

-----
Update:
It's irritating that mail boxes (and slots) are so incredibly tiny here in UK. In Denmark they are much larger, and an Italian artist friend of mine writes (after I told how my local box won't fit a stiff A4 letter):
Weird. Most of my watercolors are A4 or slightly larger. I ship them as letters using priority mail. I put the art between two very heavy sheets of cardboard, and inside a mylar bag (like those used by comic collectors) just in case it rains.
If I have to ship an even larger piece such as a canvas or large watercolor, I make sure the support is flexible and I roll it up and ship it in a cardboard tube as a "small packet" (slightly more expensive). [...]
I do the art based on the shipping methods available, not the other way around.

Digitalink said:

Forgive my hectoring tone. I am not a purchaser of fine art prints (that is those with a high price tag) but if I was, I would not buy without a certificate from the print maker detailing the production method (including the substrate, ink set, and life expectancy).

That last comment is a sad indication of what fine art prints are really about. Perhaps artistic grocery bags are the way to go.

Indeed. It was only quite late that I discovered that there are two very different art markets: the market for those who like the art. And the market for those investing in art.

Of course there's overlap, even in the mind of the individual buyer sometimes. But personally I've decided that the "high end" gallery market, where things are bought mainly on hope of later financial gain, is silly.