Not with a uke, but … a friend went to China on a religious mission about a decade ago and bought a Sigma dreadnought guitar at the factory. He was delighted to get something mighty close to a Martin for $400.
When I went to the Sigma site, I didn't see ukes listed. Perhaps they are no longer making them? At any rate, there is some info about the company on the Got a Ukulele Review page
Sigma AMI confirmed this , noting the ukulele boom died down a few years ago so they stoped producing them .
They said there were still some Sigma's available from various sources online and they also suggested taking a look at Kiwaya .