this is basically what came out of our discussion at irc:

[ 01:55:58 ] *[ @Y ] ok so originally the mangekyou sharingan was obtained by killing your friend
[ 01:56:08 ] *[ @Y ] then kakashi grows one, that isn't at all the same one as before
[ 01:56:23 ] *[ @Y ] now the two original guys with it just developed it out of talent
[ 01:56:54 ] *[ +Joker-kun ] lol
[ 01:56:58 ] *[ %DS ] which is the confirm thing i think
[ 01:57:11 ] *[ %DS ] i dont think it NEEDS a friend kill to get it
[ 01:57:16 ] *[ @Y ] yep
[ 01:57:21 ] *[ @Y ] you just need to be screamo enough
[ 01:57:27 ] *[ %DS ] i think you get a different one depending on how you got it
[ 01:57:48 ] *[ +Joker-kun ] yeah... apparently to get this "eternal mangekyou" you need to kill your bor and take his eyes, so I guess killing your best friend is just cheating to get the regular one
[ 01:57:53 ] *[ +Joker-kun ] since there's still a close bond there
[ 01:58:21 ] *[ @Y ] so basically kakashi's mangekyou sharingan is the real one
[ 01:58:27 ] *[ %DS ] yeah
[ 01:58:37 ] *[ @Y ] that explains why itachi's powers are shitty
[ 01:58:40 ] *[ @Y ] hahaha
[ 01:58:41 ] *[ %DS ] lol