This returns your Friends on Twitter who haven't gotten around to following you back, sorted alphabetically - names starting with digits first, then capital letters, then small. It accommodates up to 100,000 Friends and Followers, so there's room for growth. In case you're wondering, I ask for Friends Count and Followers Count to get them as numbers to input in mathematical calculations to loop through the right number of page requests to retrieve all your Friends and Followers. It's not hard to get Friends and Followers Counta from your TwitterID, but only as text. Yahoo Pipes doesn't currently support a way to convert text to number, which I expect will be fixed eventually.
Pipe Web Address: http://pipes.yahoo.com/toonerstan/b71827af5fc002d2bee95b1776a0a7d5