The Spacex Cricket is a very close copy of a larger toy: the Mosquito Jeep from the Hamilton's Invaders series by Remco of New Jersey. Produced from around 1964, this is a series of toys in which blue 1/32 scale plastic soldiers are pitted in a fight against monstrous alien insects, as illustrated by the Sears catalogue pictures below. The Hamilton insects may also have inspired the Cricket name for the Spacex toy.
The series is named after the large green bug, called Horrible Hamilton (nobody knows why). Next to its unusual concept, the Hamilton's Invaders range also included a cardboard cave, a child-size bug helmet as well as a gun to shoot your own toys with. :)
The Mosquito Jeep is 21.5 cm/8.5 inches long, and also exists in white and yellow variations - the latter sporting Star Trek stickers.* My example also differs in having stickers marked "Science Fiction" instead of "Hamilton's Invaders", and isn't motorised although its construction indicates it could have been fitted with the pull-string motor that powers other versions.
Apart from the Sci-Fi vehicles produced by Remco, Triang and others (see list on Cricket page to find them in the Copies & Clones section), the Mosquito Jeep was also turned into military versions by Codeg and Fook Key.
Codeg stand for Cowan de Groot Ltd. who in 1966 and 1967 marketed two versions firing either one large or several smaller missiles, available separately or together. These are identical in size to the Remco vehicle and share quite a few details.
Roughly half the size of the Remco and Codeg versions, the Rocket Launcher Mk II by Fook Key of Hong Kong fires three missiles and has friction drive.
The original origin
As its name suggests, the Mosquito Jeep is of course based on the real Jeep as used in WW2 (the two examples above took part in the 70th anniversary commemoration of the Battle of the Bulge). Whoever designed the Remco toy did a very nice job of creating a futuristic vehicle while retaining hallmark Jeep features such as the slatted grille and the combination of front wheels under mudguard wings and rear wheel wells incorporated in the body.
*: Moonbase Central has a few images of the Star Trek version of the Hamilton's Invaders series, featuring yellow vehicles and red soldiers. I saw somewhere that for this series the life-size gun was also reissued, together with a yellow version of the bug-eyed helmet.
Another military version by Molto of Spain has also been featured, where the box art suggests there might also have been a crane version in red.
And recently Paul Woods did this page an unwitting favour, by listing a lot of images of Crickets and related vehicles in a single and thus most useful post. Thanks Paul! :)