I was playing around with sending tiny payloads to space using tiny rockets, when i realized i had accidentally forgotten to stage... at all? So i wondered, how tiny can i SSTO? It turns out the answer is at least 1.43 tonnes tiny, so long as unnecessary luxuries are foregone, such as control surfaces and multiple wheels.
So here we have Little Oneleg - brought to you by the magic of reaction wheels! Just barely (72.5km/70.5km) reaches orbit, and easily lands back on the KSC runway :).