Start calling dealers and see if you can find one that has a tach in stock. Just because it's been discontinued doesn't mean it's unattainable.
You can still get the lexan part of the windshield from Cee Bailey or 7Jurock. You would have to install the metal parts from your windshield on them but it only takes 15-20 minutes to do.
Retired USAF, IYAAYAS!
2008 V-Star 1100 Custom Bobber project
2011 Crimson XR with Forged Highway Bars / Hard Bags / Passenger Backrest, Ness parts including Smooth Layback Plate Frame/Mount / Rad 3 Mirror / deep cut grips / drivers floorboards /shifter peg / brake peg / passenger pegs. Witchdoctor black rack, Lloydz filter / timing wheel / VFC III, 7Jurock windshield, Drag Specialties seat.