First I requested the meaning from dictionary.com and received this reply:
No results found for jeepster:
Did you meankeester
No, I do not mean keester.
Did Mark Bolan believe he was this car? He may have, but I doubt it.
Next stop was UrbanDictionary.com where the first meaning quotes the lyrics to the T-Rex song and the second meaning was:
a charming average guy, who is willing to go anywhere for the object of his affection---namely, a "jaguar" (a "jaguar" is a super hot girl).
So, men, if you want to make your lady feel extremely special, you're welcome to plagiarize me. Tell her you will always pillawfullaw her beanderbach! And be sure to emphasize passion while saying it.