M300LE Mixte long tail

I am riding a Cannondale from 1991 that came to be able to buy the bike myself.
(This MTB is under remodeling to the touring bicycle.)

This long tail bike I'm riding everyday for several years, previously, I was using the M500 2005 year made.

I thought long tail bike is close to Japanese traditional porter bicycles .

if so, the Mixte frame is look good in the long tail bike.
(Cannondale mixte frames are rare in Japan.)

And looking for a Mixte frame from it, finally, found the frame, it...