Alrightey, after doing some more mem searching, I came up with these:
The names of the players in the following slot numbers are saved in:
P1
00658E48
006677BB
00672B5C
P2
00658E90
006677DF
00672B80
P3
00658ED8
00667803
00672BA4
P4
00658F20
00667827
00672BC8
There's multiple places in which they're saved, and these are specificly slot dependent (I switched and my name went with it in these particular ones...)
The first values of each player numbers are offset by 48 (hex) between each other, while the 2nd and 3rd values are both offset by 24 (hex) between each other... Figuring out the rest should be straightforward... (I figure any one of these 3 can be used as a test value...)