I guess you mean a traditional sidelock percussion. Head to Dixie Gun Works. They've got a boat load of kits in a bunch of price ranges. Youmight can beat their prices by shopping around, but they've got a really good selection.And they've got a variety of Sharps rifles.

I'm just getting back into it myself and have the Traditions St. Louis Hawken on order, but that's what I could afford. I'm sure it'll do what I need, but I don't need much. If I had the money, and wanted to do some competitive shooting, I'd darn sure have gone for the Lyman Great Plains.

edit: Forgot to add the link.

http://www.dixiegunworks.com