We're totally in agreement with you, and have actually been working with a much shorter URL than the one that gets posted on the forums often. We'll be ready to put that out on the public KB soon, but I don't know exactly when ATM.
I also like your idea of posting a small blurb somewhere that talks about how to get to a short URL version. I'll discuss this with my team and see if we can work it into the real estate somewhere.
I wonder if there's a way over by the Answer ID section, next to the number, to create a link that says (copy short URL) or something like that.
Or if it can't be auto-generated, we could create a new KB that shows the short URL stub, and link to that KB from the link.
Another idea is to put a note in the Discussion Forum in that text area beneath Post Message:Reply header.
What I had in mind for a "quick fix" was to just include the short URL (since the only variable will be the KB number, should be a piece of cake - the KB # is already available, just add it to the static URL)
Something like this:
There's enough real estate over by the existing KB number reference (Answer ID) that it could go there...we could just right-click on it and "Copy Link Location" or "Copy Shortcut" and voila!
Throw some text into the page heading to explain what it's for, and you're done...