@wonderwoman, I've never seen an LII-ESE dual pair, either, and I know a bunch of LIIs and five or six ESEs. I know one LII who was living with his ESE GF, but she left him. He claims to now be with a second ESE, but I haven't met her.
My LII sister was with an EIE for a few years, but she said he was bad in bed. She went through a few men, then married an LSE, whom she said is great in bed but emotionally deficient.
I talked to another female LII about finding a Dual, and she said that Duality sounded like a bad idea, because when (she said When, not If) they broke up, she'd feel really bad, and she preferred being with a guy whom she could dump without much pain.
I do know a couple LII-LII pairs, and one ESE-ESE pair, but the pairing of these LII-ESE Duals seems to be extremely rare, in my experience.
Here is a description by Stratiyevskaya, but it seems pretty sparse.
http://socionika-forever.blogspot.com/2007/11/1.html
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Doooo iiiiiiiiiitttttt.