My lathe came with an 8" 4 jaw that I don't think has ever been used, nor kept oiled up... Im not sure how it will come out after its Evap O rust spa treatment ill be doing soon, but if its not to my liking Ill be selling / trading / buying a new one. Ill let you know..!I ended up buying a new one a couple months ago to test out the lathe. Went with Chris' suggestion and bought the same 3-jaw chuck but in 8" from Shars (link). Not high-end, but it's decent - mine is running at about 0.0015 TIR too. Happy with it for the price.
That said: the lathe is looking like a keeper, so I'm still interested in a 4 jaw and a jacobs flex collet chuck in D1-4 in case anyone stumbles on the post and has one for sale.