On Wed, 6 Nov 1996, Arromdee Kenneth wrote:

1. Tsubasa.  I love you.  I would date with you!

Hmmmm, I dunno 'bout this one. Tsubasa certaintly looks female, and
Kunou'll chase anything in a skirt......

Where is the expression "date with" from in the first place?

I thought that it was a mistranslation in one of the early Ranma Project
scripts, but I searched and couldn't find it.

"I would date with you" is a translation of "kousai shiyou"
which basically means "let's date" (dating in the sense of going steady, 
not so much as going on a single "date")  The translators have taken the 
meaning of the phrase and rendered it in a way fitting Kuno's own 
particular... (idiom, miss?) idiom!  Who came up with this phrasing 
first, I don't know, but it's pretty catchy...

mata ne,
bengman
who also knows the literary sources for several of kuno's quotes...