With all due respect, most of the picks on your list are awful. You named several artists that either hate Morrissey (Tori Amos) or that Morrissey hates (Kate Bush, Sade) or doesn't hold in high esteem (Madonna), and a couple of artists who are simply crap singers and/or produce crap music (Dolores O'Riordan
, Madonna again). And I don't think squeeky childlike voices like those of Harriet Wheeler, Bjork or Kate Bush would work with Morrissey's voice (besides, I hate their voices anyway, although I suppose you won't think that that's a strong argument
). Besides, Bjork has said that "Army Of Me" was 'about Morrissey and all the people who are like him' (i.e. who complain/whine all the time)...that gives you an idea of how much she understands and appreciates his work.
To answer the original question: Linder...of course. Listening to "Driving Your Girlfriend Home" makes me think how wonderfully their voices match and what a shame it is they didn't do a proper duet. But I doubt it's ever going to happen.
Others who might be a good idea: Patti Smith, P.J.Harvey, Marianne Faithfull, Joni Mitchell, Katie Sketch (The Organ), Annie Lennox, Chrissie Hynde, Jayne Casey (Pink Military/Pink Industry) or Cath Carroll (neither has been active in music for years, though - but then again, neither has Linder, discounting Meltdown), Kristin Hersch, Alison Goldfrapp, Tracy Thorn, Beth Gibbons, Nancy Sinatra, and maybe Amanda Palmer (Dresden Dolls). I love Siouxsie, but another duet between her and Moz is hardly going to happen, since they didn't really hit it off last time, based on her subsequent comments about him.