The big problem is how to account for localized inbreeding. Gets back to the question of if ball pythons are one big population with a fair amount of movement or if they are a bunch of isolated populations. I don't know.
I don't have the best feel for the data either but at one point I thought they where exporting about 150,000 ball pythons from Africa a year and about 3 or 4 of them where albinos each year. With one albino in every about 40,000 (picked an even number near the high end of the range) it would work out to 1 in every about 10,000 wild breedings is het to het. IF, the albino gene is randomly distributed, 1 in 10,000 het to het breedings would occur from 1 in 100 wild ball pythons being het for albino.
I've got to think that there is localized inbreeding and pockets of het albinos are more likely to breed so the real rate probably isn't as high as 1 in 100, but how much lower is it? I bet it's higher than 1 in 1,000 based on the two cases I've happened to hear of so far in captivity. Anyone have any more reports of unexpected het albinos?