Surfboardart -- 2

I repurpose old surfboard into art. I need a cutting bit, just like the standard bits that come with the Rotozip tool just longer. Rotozip does not make a bit any length longer than those pictured. You can see by the angles in the bit this is different than a "drill" bit. The the angles of the cuts on the shaft allow the tool to cut in any direction versus drilling only vertically. I would send you the actual bit(s) for reference. Specifically, I need the "cutting portion of the bit" elongated to be 3.5" long, the shaft which inserts into the Rotozip tool may remain the same, 1". Therefor the total length of the tool would be 4.5 inches in length. I will require a CAD drawing made so that I can hire someone to 3D print bits for me. Takers? Cost? Timeline? Thank you. Paul