zpkunkle,
I don't know if Scherl-Roth made any, but Roth-Finch made 3/4 fiberglass basses (and perhaps other sizes) during the '60s. Scherl may have been the distributor, but I don't recall their name associated with the basses. Ron Carter endorsed the instrument and the ads ran in Downbeat and other music publications of the period.
I purchased an old one about 14 years ago that was not setup, no bridge, tuners, endpeg or soundpost (plus someone spray-painted the thing a dark red). I was going to use it as a project, but that probably won't happen. I've heard various opinions over the years about their sound, some good, most bad. The thing is heavy, I'd estimate about 1 1/4 to 1 1/2 times that of a wood instrument and would be heavier when completely setup.
WRT carbon fiber basses that Andrew McGregor mentioned, there's only two manufacturers of them that I know of, Luis and Clark in Massachusetts, and Quintus Strings in Arizona. Although Ed Fugua, in the 150911 thread link below, stated he played one in France in the late '90s:
http://www.talkbass.com/forum/showthread.php?t=150911
There's a few threads over the last three years on carbon fiber basses:
http://www.talkbass.com/forum/showthread.php?t=211985
http://www.talkbass.com/forum/showthread.php?t=205109
http://www.talkbass.com/forum/showthread.php?t=232932
And here's a thread that mentions carbon fiber basses, but more directed to the functioning of Wikipedia;
http://www.talkbass.com/forum/showthread.php?t=150911
Here's another link at The Associated Board of the Royal Schools Of Music regarding carbon fiber instruments.
http://www.talkbass.com/forum/showthread.php?t=211985
Quintus Strings' site is available at the following link and they offer different finishes on their instruments:
http://gracestrings.com//basses.html
Note that these carbon fiber basses are pricey. In 2005, Luis and Clark's price for a 3/4 was about $8,000+, and their current price is $12,939. Quintus lists their 3/4 for $7,200. Someone mentioned that they could buy 4 plywood basses for that price, but I think you'd be paying for the different technology and the increased durability. I would expect that the sound quality will improve from where ever its at currently, but whether it will sound 'better' that a quality wood instrument - well, that's something else.
Personally, I wouldn't put too much into an old fiberglass bass (I've jokingly thought of how it would look as a large, rural mailbox in front of my house). If you really need something that will survive a tumble on land or use as a floatation device if your ship sinks, then carbon fiber has probably got some points going for it. I'm not really trying to be facetious. I though about a carbon fiber instrument when I was considering the cruise ship environment, although I haven't completely ruled that out yet.
Lloyd Howard