I had a hand a few minutes ago at NL O/8 where two of us ended up all-in preflop with a 49.99% - 50.01% equity distribution. Virtually as close to a true coin flip as I've ever seen...
The hand was: my JsAhAc9d vs. his AsTc2h7s.
Out of 1,086,008 possible boards:
347,212 -- I win.
347,512 -- he wins.
391,284 -- we split.
I got unlucky this time, as my Aces didn't improve and were cracked by -- of all things -- his offsuit seven-deuce.