I had a very tough time finding rings. Check with a local machine shop.
A few words of advice though. The minute you unbolt the piston rod end caps and the main bearins, you want to align bore the block and have each piston rod checked etc. Most guys that try to rering or change bearings w/o extensive machine work end up with a bad bearing/crank about 200 miles later. Our motors are very picky about these things.
One other tidbit is that our rings are not a high pressure pushing ring. Therefore at 186K when I pulled the pistons out of my old motor (see 200 mile lesson learned) I found the factory cross hatches were still visibile. A mechanic buddy helped me rering and told me that the stock rings had tons of material left. Much more than any nearly 200K mile motor usually would. I found out after more researching about how the rings don't wear much and the align boring.
00 Regal GS: All kinds of cool stuff.