I wouldn't worry about these guys going under. I have been working with them (I sell LEVEL stuff up here in Canada). Every manufacturing run these guys do sell out in a matter of weeks...We are constantly waiting for them to do additional runs.
As well, we've been stocking up on cogs just in case any ways
I've talked to them about a smaller cog than 15T as well. Because these were originially designed for Fixed MTB'ers is why they only go to 15T...they may be putting out 13T and 14T though in the future.