Okay, so following the storm of everyone who answered so far (even if I wasn't the one to start this thread in the first place - blame Getta One for this!), here is a small compilation of every suggestion that's been thrown my way so far - thanks to those who helped.

*Warning*  This list *may* contain some mistakes - it's what people sent me...

EVA possible switches:

Shinji:
  Haruka Ten'ou (Sailor Uranus)
  Yukito Tsukishiro (Card Captor Sakura)
  Eagle Vision (Rayearth)
  Princess Emeraude (Rayearth)

Rei:
  Atsuko Natsume (a.k.a Nuku-Nuku)
  Onna-Ranma (Ranma 1/2)
  Lina Inverse (Slayers)
  Pai (3x3Eyes)
  Faye Valentine (Cowboy Bebop)
  Lime (Saber Marrionette)
  Hello Kitty

Asuka:
  Linn Suzuki (Kotetsu)

Asuka's father (?):
  Mousse (Ranma 1/2)

Misato:
  Usagi Tsukino (Sailor Moon)
  Mink (Dragon Half)
  Mihoshi (Tenchi Muyo!)

Kaji:
  Ryouga Hibiki (Ranma 1/2)
  Largo (BGC)
  Spike Spiegel (Cowboy Bebop)

Kaworu Nagisa:
  Xelloss

Touji:
  Gai Daigouji (Nadesico)

Maya:
  Miyu (Vampire Princess Miyu)
  Izumi (Nadesico)

Hikari (the class rep)
  Tomoyo  (Card Captor Sakura)
  Tomoe (Ruroni Kenshin)

Aoba Shigeru:
  Hotohori (Fushigi Yuugi)
  Kiryuu Touga (Utena)
  Rezo (Slayers)

  If you really need to bug someone, bug Getta One - *he* started it...  :)

  Getta One, you started a monster, I fear...  :)

  Well, that's it.  Now, let's tone this down a bit before Alan "Moderatormon" Harnum digivolves into Threadbanmon, then into Tempbanmon (who can even evolve once more into the the very-much feared Permbanmon)...  :P

**********************       Jordanite and Mystical
* The Phoenix Reborn *           Freak at Large
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                       * dragon@anime.sobhrach.com *
Louis-Philippe Giroux   * phoenix@cephiro.com       *

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http://www.anime.sobhrach.com/~dragon/

"Oh, it's just a bird... a *large* bird, I grant you.
A large *angry* bird - Aaaahh!"
 -Phantomon, just after causing Biyomon to evolve
  into Birdramon