LACC North would be an excellent US Open venue. A little on the short side now though.
That would be an awesome venue. They'd probably move the tee up on 1 though, to make it par 70 and a 490 yard downhill par 4.
As for making the course longer, that might not be easy to do. Holes 2,3,5,6,8,9,10,12,14,15,17,and 18 (maybe 5-10 yards if possible) do not allow for any more room to extend the tee back. Hole 4 could be made into a 230 yard par 3, that's an extra 25, and 11 could be pushed back to make it around 260, but that's not really necessary.
I think the only hole that could be lengthened and have any effect is 16, but even on the holes that are lengthened the fairway bunkers are not really in play for today's pros.
Unfortunately a U.S. Open at LACC would require Rees, and I would love to see that course stay as is. I've played Riv and LA and actually enjoyed LA north more.