So I saw a video on YouTube of a guy with a quarter step acoustic guitar, every fret was a quarter step instead of a regular half step per fret. He was making some cool, dissonant sounds, obviously because of the smaller intervals between notes. There's no way I could get me one of those guitars at the moment, but here's what I was thinking;

I could tune the A string down to E, but a quarter step above E. So the strings would be E, E1/4 up, D, etc. When you would play the sixth and fifth string together, it would create that very dissonant sound. And then if you played the 1st fret together on both, it would be dissonant too, an F and F half sharp(no idea what you would call that note). I could make the same sound as that quarter step guitar, without actually having one. In theory, this all makes sense to me, and hopefully to you too. My only problem is getting that A string to the 1/4 step above E. How would I do this?

This probably doesn't have a practical application, but I'd still love to try it for experimental purposes.
well, I have a korg tuner CA-30 just the basic little one that everyone has it seems. And it has the "cent" markings on it. I supose you could use those to find the halfway point. also you can raise the pitch it tunes off of. so like normally you use 440 but you can change it to like 460 or whtever. just a thought

Also I did something like this once and used my amps built in tuner and tuned one string down until the tuner went from saying Bb (is a little flat) to A (is a little sharp)
no sir away a papaya war is on
You could also slightly bend pitches out of tune. This would not require you to detune your instrument.
wear thimbles on your fingers so they act as slides and that will allow u to play any pitch

Tell me what nation on this earth, was not born of tragedy-Primordial
hmm if you had a 12 string you could tune every second string a quarter step down, then with some careful picking you'd have the entire spectrum