Does anyone know why IS disambiguations are not in alphabetical order? It is really hard to find the right one when the list is extremely long.

Has anyone raised this before? Is it very difficult to do technically?

It has been raised, including when it was introduced at first, but surprisingly seldom. 'They' don't seem inclined to do anything about it.
You could raise the point anew, I guess, e.g. in the suggestions or keyword forum, but some smarty will probably just point you to where it's been mentioned before.

Quote from: Freedom on May 21, 2009, 16:22

Does anyone know why IS disambiguations are not in alphabetical order?

They are in alphabetical order, you've just made the same common assumption that many others have.

A while ago iS took the alphabet as it is known to buyers & contributors the world over and they rearranged it to form their own unique alphabet, similar to what they did with the CV. 

Yes, it's know as their attempt at disambiguation of the alphabet.