has anyone ever tried a really rough (500, 360) surface on a really weak ball like a twist or something like that. i know some people sand plastic and urethane but anyone tried it on an entry level reactive. i thought maybe with a weaker cover it might work better than sanding something like a kingpin or crux (yes i did sand my kingpin to 360 to see what it would do).

Surface dictates length.  So do you want a weaker ball to slow down faster?  Sometimes.
Can you get so much surface that the ball changes direction too slowly? Sometimes.

So much depends on how much oil you're seeing, ball speed, rev rate, and your individual style.  Not to mention lane surface.  If you have the hunch to try something give it a shot.  You can always smooth out the surface more if it doesn't do what you expect.

I would worry about carry. Putting that much surface on a ball with a weaker core seems like it would burn up quickly and not have enough engine to get the ball through the pins. I think it's worth a shot if you already have something low-end in mind to experiment with, maybe not so much going out and spending on a brand new ball for that purpose in mind.

But... if the weakest ball you have is a Venom Toxin something like a Twist might be good anyways. Just bring is back to box afterwards if it doesn't work.

I go 1000 on a Ride, love the results but I tend to leave a lot of 10 pins. 

Allow me to insert my patented After Dark Pearl with a 2 inch pin response in here.

Seconded

Yes, I have. I put a 180 abralon on an old 1995 Track Nrg (weak, slow response resin) on the flat and heavy 37 foot Melbourne oil pattern. It actually work great playing straight up the ditch (at least the first 2 games it did). I have also used an 800 grit scotch brite pad on a tropical breeze for one the houses that has good head oil and FLYING backends. The two biggest issues with this much surface on weaker resins is that they QUICKLY shine up after a couple games and they tend to burn a line in quicker than usual.

If you have at least medium-medium heavy oil on your league shot, a twist even with 500 is NOT going to burn up on the fresh. The twist is virtually allergic to any significant oil volume. I don't care how much surface you put on that ball, it has a low ceiling for oil handling ability.

Honestly, I would NOT recommend using a lot of surface on a weaker resin for the reasons others and I have stated. It just lacks versatility. It would hook too early on dry heads and still skate through any kind of significant volume.

500 on an extremely low diff ball makes it very difficult to get any recovery on the lanes and such a base coverstock is so weak that even with that much scuff it would either still be touchy or prone to a quick lane shine.  There is probably a pattern out there where it will work, but in general I wouldn't feel much confidence in attempting to carry the corners.
I prefer seeing stronger (2.5-3" pin to pap) layouts on weaker (rhino, alley cat) but not weakest (twist) balls with a good amount of scuff (1000-2000) and using them to play the track when seeing a drier, over walled THS. 

I shot my first 300 the day I sanded a Brunswick Slingshot down to 500.  It was not the ultimate solution to all my problems, but I certainly didn't need to worry about it jerking left on the back...