Best alter self tricks for prestige class entry?

[CaDzilla]

Was reading this thread (http://www.giantitp.com/forums/showthread.php?369579-How-to-use-Beholder-Mage-to-level-10-without-going-into-epic-levels) and was wondering, what are some broken uses of polymorph type spells to enter PrC

[paperarmor]

Maybe Illithid Savant? But that's kind of 6 weeks in the sun gouda if it works. You might be able to do other such things as a dragonwrought Kobold.