OK, how about a new thread:

Albums that kinda sorta got released, but in such small quantities
and with so little (or no) promotion that most people don't even
realize they got released. I'm talking about major label attempts,
because obviously some no-name band on some miniscule label will generally
also be invisible to the mainstream...

Here are two off the top of my head:

The Keys: The Keys Album. A&M, 1981. 

Produced by Joe Jackson. A pretty good retro pop/rock album with a few
knockout cuts ("I don't wanna cry" is an incredible Merseybeat influenced
track). It got a proper release in the UK, I believe, and it got
pressed and serviced to some people as promos here, but I never saw one
line of promotion for it, not a single review, not a single mention. The
only US copy I've ever seen, in fact, is the copy I bought from the $1 bin
at Rasputin's in Berkeley in 1981. (And no, it's not an import serviced
to the US, it's a US pressed [Columbia pressing plant, as were most A&M
releases of that era] LP). It's a normal commercial copy with a 
"not for sale" promo stamp on the back. I could never figure out what happened...

Head for Tall Trees. Chrysalis, 1987.

I believe they were a North Carolina band. A decent pop effort. As far as I
can tell, only released on CD. In 1987!!! I've come across perhaps 3-4
copies over the years, all surely promo service all CD. I've never seen a
vinyl copy of the album (and with the time I've spent at the bins, I would
almost surely have seen one if it existed). Never saw a review. Never saw
any press. It just seems like Chrysalis must have dumped a few CDs on the
market to fulfill some sort of contractual obligation. I can't imagine there
were any other CD only releases (excepting promos and the like) in 1987. 

dap