First factory made muscle bike was the John T. Bill & Company Penguin made for them by Huffy, released on March 3rd 1963. The Stingray was not released until June 1963 after seeing the success of the Penguin bikes...
Leon Dixon of the National Bicycle History Archive of America notes regarding the Stingray being the first: "This is a very serious myth. First, Schwinn merely copied the Huffy Penguin which existed BEFORE the Sting-Ray. And these bicycles were pioneers in the 20-inch bicycle revolution/genre, but certainly did not necessarily father BMX. AND... the first Sting-Ray was officially stated by Schwinn as being NOT a 1963 model, but officially known as a "1963-1/2" model. Either way, Huffy was on the market first."
http://bikerodnkustom5.homestead.com/br ... uscle.html
http://www.jimlangley.net/ride/bicyclehistorywh.html
Anyway, the penguin and Stingray frames are not that dissimilar, and if you want something like them have you considered a Bratz bike frame? They are cheap and plentiful, the chrome parts on them are cheap and horrible, but the frame itself seems ok, might give you what you want without breaking your price barrier.
This bike was made from a Bratz frame by Peatbog, one of the nicest bikes around:
viewtopic.php?f=67&t=56351&start=0&st=0&sk=t&sd=a
If you are not fussed about that particular frame shape, but want the muscle bike look with big apehangers and a banana seat, there are some very nice bikes out there, try looking up Murray Eliminator 1 and 2, Iverson Dragstripper, Huffy Rail... Not saying that all of these will be in your price range but might give you ideas with a frame you already have or can find cheaply. Other brands such as AMF or Columbia made Muscle bikes too, and can sometimes be found cheaply.
Check out this wiki article for more information. It states however that Muscle bikes only had 16-20" rims which is not true, there are a few examples of 24" muscle bikes and those are highly sought after for larger adult riders.
http://en.wikipedia.org/wiki/Wheelie_bike
Luke.
P.S. Most of those photos come from this site, just takes some searching to find them sometimes...