OK, I realize that 99% of what Casey Anthony says is a half-truth at best, still, I've been re-listening to Casey's phone call to Lee @ end of July that includes info on her other (i.e. "BlackJack") cell phone.
IF, we play along for a minute, and, indeed, there WAS another cell phone (i.e. "BlackJack" or other) Casey appears to be TRYING to tell Lee that she tossed her cell phone @ Universal Park when she was taken their by LE, 7/16. She indicates the last time she had it for "certain" was when she was in through the park "in through the park talking to a couple of mutual friends", and "it wasn't necessarily fun" and "not through work". At this point she knows the calls are made public and must try to get the point across indirectly.
She later indicates that these "mutual friends" are the ONLY ones she talked to about Caylee missing. The two names she gives are complete fabrications (oh, how ironic) and she disagrees with the spelling of Juliet to try to clue Lee into what she is trying to tell him, but, he doesn't get it (i.e. the mutual friends are the LE that accompanied her 7/16)!
She also indicates "J Blanchard Park" as a potential place she lost it too to try to clue Lee into what she is trying to tell him - as in places she's been escorted around to w/ LE 7/15-7/16, but, he doesn't get it.
She is VERY emphatic about telling him how it might've been lost "that's the thing...if it fell out of my bag...if it fell out of my pocket [LONG PAUSE i.e. "DONT YOU GET IT?!?!?].
My hope is that LE figured this out some time ago and retraced Universal route they took on 7/16 (i.e. Did she go to a restroom unmonitored?), and checked the lost-and-found @ Universal for any/all cell phones. IF there indeed was another cell phone Casey used, regardless of what type, it may have been tossed in a place where it would be hard to tie back to its original owner.
Casey may have stolen the second cell phone to use when she needed to go undetected, and, hence, didn't have a charger to use. J.P. Chatt immediately went shopping for an iPhone the day he returned from Puerto Rico, suggesting that something had happened to his phone.
J.P.s phone records would be worth a search.
Dunno about the compatibility of the sim chip between Caseys phone and the other phone. Maybe just a complete ruse there.
Perhaps not new ideas, but, just in case, I thought they were worth sharing.