I put hardwood floors into my condo around a year ago. When doing that I thought it would be nice to have hardwood stairs, but doing the stairs is a lot of work so I didn't. Now I'm going to tackle the stair project.
This website sells reasonably priced custom treads and risers. I just placed my order so I'll give an update on quality after I get done with this project, but reviews say this place is good.
In order to know exactly what to order I had to figure out exactly how I was going to install the new stairs. To do that I needed to remove the carpeting, banisters, and handrail. It took a little figuring, but I got it done. It will be awhile before I can finish this project so the house is going to be in this incomplete state for awhile. Below is a timelapse.