I don't know if anyone specifically sells one as such. I believe that Power Custom offers something of the sort in the way of a replacement trigger and hammer that have had a "trigger job" done on them. The cost of this pair is quite a bit more than you would pay to have your trigger done by a competent gunsmith.

In truth, to reduce the trigger pull and smooth up the action, you need to reduce the weight of the trigger return spring, remove rough spots on the internal cast parts and polish as appropriate, apply trigger grease where necessary, and work on the sear engagement surfaces. All of those items will smooth the action and reduce the trigger pull.

You can do a cheap and easy trigger job on your own by simply removing the grip panels. With the grip panels off, notice the "legs" of the trigger return spring on the top of each side of the grip frame. They are resting on the two protruding silver posts. Using a small pair of needle nose pliers, gently lift one leg off its post and carefully bend the end of the spring "up" toward the hammer. You want to create the "new" bend in the spring about 1/4" from where the current one is. You will be creating a sort of "dogleg" in the spring. Now place the leg of the spring back on the post. Repeat the process for the other side. Go easy at first and bend a little more if you want to try some more. Worst case scenario is that you ruin the trigger return spring and need to buy a replacement. If so, it is a cheap lesson.

You could also buy a replacement trigger return spring and reduced power hammer spring from Wolfe. I am, however, reluctant to use reduced power hammer springs unless absolutely necessary. I can usually improve the trigger pull on a BH sufficiently with a regular power hammer spring installed.

If you don't want to experiment on your own, shop around. You can probably find a local smith to do a good trigger job for you. Expect to pay $50 - $100. It will be money well spent.