[Zugaxxsn]

Okay, so I'm probably off somewhere, but these are my thoughts on the I/M probability...

We know that the draw is 128, but since both are unseeded, we know there are 32 places where they won't be, leaving 96.

Now, I'm sure the probability would shift depending on when they were placed, but let's say Isner was the first person they placed. There are 96 vacant spots, but 32 of them yield seeds, which will prohibit the matchup. With my very rudimentary probability skills, I would say that Isner has a 2 in 3 chance of nabbing one of the unseeded/unseeded matchups.

Then, let's say Mahut was the next to be drawn. He would now need to be placed in the only spot that yields Isner as a first-round opponent, so he has a 1 in 95 chance of getting that spot.

If you multiply the two probabilities together, you get 2 in 290, or 1 in 145 odds that the matchup happens.

Note: I am not a math person, and I'm sure there are other variables that I'm not taking into consideration, but this might just be one way to look at it.

Sorry to have bored you.