The MouseSaver newsletter is due out in a few days (on the 15th of the month). Apparently there is usually a link in the newsletter that gives you a slight additional discount on Disneyland tickets from
Undercover Tourist (and they don't publish the link on their website, so you have to get it from the newsletter). I haven't used it, so I can't vouch for it personally, but for those who (like me) were planning to buy tickets from Last Minute Travel, this seems like it might be the best alternative if Last Minute Travel doesn't get them back in stock soon enough for your vacation.
I just thought I'm mention it. If you sign up now, you won't have to wait another month for the next newsletter. Here's the link:
https://www.mousesavers.com/mousesavers-newsletter-signup/