Considering the ACTUAL crossdressing in the game lasts all of 3-4 minutes, it's funny how a good 30%+ of the fan art revolves around it. But I agree, it adds to the humor and awesome here.
Honestly, it'd probably be better if Yosuke and Yukiko swapped outfits, if only for their battle skills. Then again it's kinda impossible to match all the characters up like that.
A) Minato Arisato = Seta Souji (Obvious reasons) *Note: Just if you don't know...those are the names used for the protagonists in the mangas of Persona 3 and Persona 4
B) Takeba Yukari = Satonaka Chie (Both have the same bad humor and a sort of pissing-of-girl actitude)
C) Jumpei Iori = Hanamura Yousuke (Both of them are the lazy, stupid-humor sense, take-it-easy guy)
D) Amada Ken = Dojima Nanako (well..it was good that way...and there weren't any other options I guess...^w^U)
E) Aragaki Shinjiro = Tatsumi Kanji (Just perfect...)
Then...there are some troubles....
F) Yamagishi Fuuka = Shirogane Naoto or Amagi Yukiko?? (Maybe because both of them are a bit introverted, that's why I think one of them could do Fuuka's role...but then again...they have some diferences...)
G) Aigis = .......Teddy (Let's face it guys..we all did see that coming....but..guess that doesn't make it easy to digest...-w-U)
As for Sanada Akihiko and Kirijou Mitsuru there are not a certain character in Persona 4 who can fully crossdress them.....in the case of Akihiko, Naoto was a good election but...she doesn't seem like the "let's get 'em all" character, as Akihiko tends to be...)
And as for Kujikawa Rise...I'm pretty sure there's not a certain character she can crossdress....