Yes, I believe the Powers Custom makes one, black or stainless, but call first to confirm, the description is confusing:
http://powercustom.com/store/index.php?main_page=product_info&cPath=12&products_id=113
But it ain't cheap however you do get a 1/2 cock position. Or grind off the notch to function like a factory hammer. Although removing the hump on the Ruger factory hammer is not all that hard! If you want details just ask.
Ya just need to test any hammer swap to make sure the transfer bar safety is still working properly:
#1. Safety Testing AFTER CHANGING HAMMERS IN NEW MODELS:
The first thing to check is the transfer bar clearance with hammer for reliable firing pin function. When swapping hammers between two guns, it often helps To swap transfer bars as well for proper ignition and to insure the safety feature still works correctly.
TO TEST HAMMER/TRANSFER BAR FOR MISS-FIRES:
With hammer fully cocked, press on the transfer bar to extend the firing pin and observe how far thru the recoil shield it protrudes. Now keep the trigger pulled back, drop the hammer and observe the firing pin again. If firing pin protrudes the same amount, you're good to go. If it doesn't protrude the same amount, you need to remove just enough metal from the top face of the hammer nose so the transfer bar is pushed tight against the firing pin and the frame. If you remove too much, the transfer bar will not perform its safety function and will be pinched. Also make sure hammer has no friction or contact with grip frame ears around its base to slow its fall and you may have miss-fires; another potential issue when making hammer changes.
IF TRIGGER DOESN'T RETURN, TRANSFER BAR IS PINCHED AND SAFETY IS NOT WORKING:
If the transfer bar is hanging up under the hammer face, since it's connected to the trigger, it prevents the trigger from returning. The transfer bar is slightly too thick. If both ends of the trigger return spring are connected (under the grips), or even if you have only one leg of the spring connected it should pull down the transfer bar if it's the correct thickness. When this happens, the transfer bar safety function will not work. If the gun were dropped, a live round in the chamber under the hammer will fire.
This is not uncommon however, and it's a very simple fix. File the second step of the hammer face, counting from the top, just a bit until the bar no longer hangs up. Don't take too much off or you'll have miss-fires. If that happens file a little more off the top step of the hammer.
IF YOU HAD TO MODIFY HAMMER NOSE:
At the range, double check the safety function by loading a live round in the next chamber to cycle under the hammer, point down range, cock the hammer, hold with thumb, release the trigger to uncock the hammer, take finger off trigger and release your thumb to let the hammer fall. The round will not fire if safety transfer bar is functioning correctly.
#2. MY SHORTCUT FOR REMOVING JUST HAMMER and/or PAWL in New Models:
Recognize, when JUST NEEDING to remove the hammer and/or pawl, you do not need to hassle with the PESKY LOADING GATE SPRING, pull the trigger pin, nor trigger/transfer bar. Once you remove the grip frame, the hammer pin is the only other part you need to remove. After that, just pull the hammer back and all the way down, then depress the hammer plunger up into the base of the hammer with a small tipped screwdriver to clear the trigger extension with hole in it where the transfer bar connects to it. Let the hammer & pawl fall back, down and out. Reinstall the hammer and pawl back in the same way they came out. Push the plunger in by pushing it against the trigger extension just like you did with the tip of the small screwdriver, and the hammer will slip by the trigger extension. Piece o' cake.
NOTE: Occasionally a changed hammer that doesn't cock or just barely cocks is because it's hitting the back of the slot in the grip frame. I have had to slightly lengthen the slot with a few file strokes.
If either the trigger or hammer pin are snug fits, after they're removed the first time, it's the opportunity to polish them so they are slip fits to put back in and remove the next time.