Maxima? I mean, it traces its lineage to the golden age of Lisp, but it's still being released.

And you say Scheme was friend-zoned by the industry. While I understand why this was, it's a shame: Scheme is a very nice language, and with several high quality implementations, some excellent FFI, and finally some good library support (CHICKEN is excellent here), not to mention Racket's deluge of features and libraries (not really a fan of it myself, and it's not scheme, but I'm willing to admit it's a good system, to say nothing of impressive), it's finally slowly reaching the point where it might be usable in an industrial environment. Although it's not there yet, you can definitely write useful things in it.