I'm pretty sure Dave Carey (cargostar) offers the LoneStar daycab conversion. He's a member here, so check with him.
As for the Kenworth, it sounds like it could either be a W900S or a T800. If it has a set back front axle, it's probably a T800. For that conversion, I'd check with Gary Wallace over at GW Trucks (gwtrucks@yahoo.com). He has the T800, T800W, T800H, & W900S conversions. They're about a mid-1990s cabb.