How to simulate a 1000 IBU beer:
1) Buy/brew a nice, strong IIPA, or similar
2) Put 1/4 cup of said beer in a glass
3) Add 1/4 cup of high %AA hop pellets
4) Mix ingredients well
5) Drink, and attempt to keep contents in your mouth as long as possible
I've had the Mikkeller 1000 IBU beer, and while it was (very) bitter, it was nowhere near 20x as bitter as a nominal 50 IBU IPA.
If you've got plenty of money to waste on an excessive hop bill, and a mindset that just says "yeah, f^%k it, why not?", then go for it.
For the sake of 5 hours brew time, plus tying up a fermenter for 2+ weeks, I'd brew a "low hopped" IIPA to around the 80 IBU mark. It's still going to be more bitter than my ex's opinion of me.