This isn’t exactly what you’re asking for but… I used a few MariTool machine drills in combination with their incremental sized collets with great results on the Pro 5. I was only drilling in hardwood but they bill them as suitable for metals.
MariTool Carbide Machine Drills
So I had also inquired to Harvey when I was looking at those. Their support actually suggested interpolating with a smaller mill where possible…they didn’t mention the mill drills.