Wow - I love how this sounds ! After reading many articles before about mic techniques for acoustic guitar -I can't recall this one ever being mentioned -until this article I found in the Knowledge Base (and too dumb to figure it out on own!):
 
http://www.cakewalk.com/Support/kb/reader.aspx/2007013311
 
He favors this one over all 10 mentioned in article - it makes a lot of sense to capture the hi / low strings in this way. Then when I pan them hard R & L - sweet. Nice blend of hi and low. To me this sounds even better than the M/S method which I thought was pretty good.

The article does not say how far the vertical spaced pair is from the guitar but I gather they are fairly close. This does look interesting and I could see why the stereo effect is nice depending on strum direction etc..
 
I found it interesting listening to all those examples in the Cakewalk article. I prefer the stereo micing setups by far. Interesting how the tone changes quite a lot with any of these configurations.
 
One mistake I think that Cakewalk made though was in positioning. I actually liked the vertical spaced pair a lot and also the good old XY except pointing those setups at the soundhole was a mistake in my opinion. I can hear the boominess in both of those. But maybe positioning either of those away from the sound hole and up towards the 12th fret more I am sure would remove a bit if excess boom and improve the mids and highs slightly. Experiment I think is the answer here.
 
I did not mind the MS setup either, it sounded quite nice too, but it too needs to moved away from the soundhole a bit. I have found from experience the soundhole is not a great place but it does depend a lot on the guitar of course. I have a friend who has two Martins. (I have recorded them often) One is big and loud and fat and the soundhole should be avoided at all costs. The other other one though is light and quieter and great for pickin type stuff. The soundhole is OK on that guitar. In fact it puts a bit of bottom end back into the sound.

 Actually, I do the Blumlein Configuration (#1) quite often with good results.  I have also used this a lot lately for vocals.  The pair of mics that I use are not expensive, but seem to compliment each other nicely.  Then, I can also blend them to taste.

Same on the not very expensive mics - but they are sounding good blended. I should but don't have a matched pair of small condensers but one is a Sterling Audio 33 that was not exactly cheap and sounds really good. MakeShift I see we have two things in common - Texas, and the Focusrite 8i6...

Am gonna try the vertical spaced pair, sounds interesting. Thanks for the post on this.

I might sound like a broken record with this post but check out the dozens of sample videos at soundpure.com  They are a retailer that specializes in high end recording equipment and guitars.  The favorite method is a spaced pair, one a foot or two from the frets, and the other over the right shoulder pointed at the soundboard.  You might call it an angled spaced pair, in-between traditional AB and vertically spaced.  

I have heard of the "over shoulder" method - to simulate the perspective of what the guitar player is doing. Again I guess its a matter of taste on all these different configurations. Thanks for the site link - will have to take a look.

I used the over the shoulder method recently as well. It gave the acoustic guitar more depth, in my opinion. It was used on my song, Breathe, at my Sound Cloud site. I guess I have been doing a lot of experimentation lately with dual mics.

MakeShift Do you record guitar seperate and then your vocal, or a set up with you singing and playing at the same time? I tried that (again watching some tuts and article in Recording mag) for recording the singer / player at once. I got some decent results but still struggle with balancing things out well - and keep tending to prefer the seperate tracking / overdub method, to have more control over things / processing.  I need to keep trying though cause it can sound more "organic" to do both at the same time...  Just have to strike a good balance as to capturing guitar and vocal and not worry so much about bleeding.

Most of the time separately.  I have recorded both vocal and guitar at the same time, but it is a really big feat for me to be the Engineer and the subject at the same time.  to many moving parts to focus on all at one time.  If some one else was tracking me while I was playing, it would n't be so hard to do.  My main focus when Engineering it to get the best takes of everything at the time of tracking, so I focus on that instrument or vocal, singly.