From what I've read, there are four attested types of adpositions. Prepositions and postpositions are the most common, but circumpositions (discontinuous morphemes that occur around their objects) and inpositions (incorporated into their objects) have been attested. So have ambipositions, which may occur before OR after their objects. http://www.glottopedia.org/index.php/Adposition
But, among natural languages, is there such a thing as an adposition that occurs once before the noun that the prepositional phrase modifies, and once again before its object. e.g. Is there a natural language that says "IN an avocado IN the jar" to say "an avocado in the jar"?