Ed,
Sometimes they do look pretty big when they are building, however, my guess would be ovulation. What I would do, is watch her close, and look for her shed in about 10 days. As Becky said, she will also probably migrate to the hot side (if she hasn't already). I know you said you palpate horribly, but after she sheds, try again, as the eggs are alot bigger than the follicles (the problem is that eggs are softer than follicles), so this may cause you to miss them as well.

Side note: let this be a lesson that not all Ball Pythons have been to Mark Mandic's website, and they do not know all of the signs that they are suppossed to give you. They don't always give you every sign, and sometimes they give you none.

Hope that helps,