Thank you for replying and considering this topic Nance!!

(and I recommend watching the film again! I hadn't seen it in years and it's gone back to being my absolute favourite, even though it's 21 years old, I think that might say sth about the quality!
Lol Kenny G, could be, but I also doubt it. I reckon it's been made by some poor musician banging out music like this for the studio where nobody ever thought anyone would wanna know where it came from lol
I don't know how they did it back then, today everything seems to be outsourced to small music studios like Brand X. But back in 1990, when films where made a bit more haphazardly than today, I can imagine someone just knocked that out in a day or two cause they said they'd need something for the trailer. I mean it's not very complicated music, more like a carpet.
But it is that direction. David Sanborn would also have been too famous and distinct I think.
There is a similar music to the one I'm looking for at the end of 'Blast from the Past' (1999 with Alicia Silverstone) called the Adam & Eve love theme.
Adam & Eve Love Theme- Blast from the past 1999 - YouTube
It's the same soppy music (which I'd like to stretch again I have a soft spot for though!
Thanks for the St Elmo suggestion. It is also very close! But not the one track yet (but apart from that the film looks like I could enjoy - thanks for that!
And you're right, it is more 80s actually. End of a decade I guess.
As far as I know the Jack Nitzsche soundtrack hasn't been released for sale. That is, if indeed he composed a soundtrack. On Wikipedia he seems more like a guy who did stuff for bands like the Stones etc., so I'm not sure he'd compose something 80s softy like this, especially just for the trailer. I haven't been able to find out yet, if he just compiled existing music for the film.
Here's my other 'Mermaids' thread about the classical soundtrack:
http://adtunes.com/forums/showthread.php?t=102982
I've been thinking of contacting MGM (who after Orion went bust now own the rights to 'Mermaids') and asking. Has anyone had any good experiences with that? Like are they helpful at the studios, or more horror stories to tell? Can I send it to the general email (guess I'll have to seing as they're pretty guarded and I wouldn't know what department handles archiving of older films anyway)?
But the suggestions so far are on the right track and thank you very much again Nance!