With a long enough runway, virtually all things are possible! But is it practical? - that's another thing!
It appears that I'm fighting a losing battle here ... however, for the benefit of the new chums whom I don't wish to get quite wrong ideas, I shall continue ..
In determining the maximum weight permissible for a given set of circumstances, we have to run a bunch of sums covering a range of things, including runway, obstacles, WAT, etc., etc.
For those who haven't run the AFM calculations by hand to see just what is involved it can seem that it is a bit straightforward .. ie just look up the RTOW chart or feed some numbers to the computer and read off the answer.
Just having a long runway doesn't cut the mustard unless the other bits are looked at in detail as well. Whichever of a bunch of limitations gives the lowest weight becomes the limiting case for the day ...