As well... from what I remember seeing over the years, youre more likely to see 4 jaw scroll chucks rather than 3 jaw. (likely because most turning blanks come square instead of round. So if youre not finding much when you search for 3-jaw... you might change to searching wood working tool sites for "lathe chuck". Im not familiar with all the brand names off the top of my head... but One-Way Barracuda and I think maybe PSI pop into my head - and I think they are all 4 jaw scroll chucks.
Wade