I used iGaging DROs and built my own mounts with decent swarf shields and they’ve been working great for at least 10 years. They can be hacksawed to any length… and they’re cheap. Companies that make the fancy ones usually offer sets sized for various drill-mills. Have you checked Grizzly?

You might join the drill-mill group and ask there. It used to be a Yahoo group like this one and unfortunately all the nice photos and stuff disappeared. But some of the same guys are there and will likely give you some advice.?/g/Drillmill

Gary