Just out of curiosity, why would you want a kit? It's unlikely that the room's dimensions are a perfect match for the increments the kit parts come in, so some actual cutting and fitting seems inevitable, at which point it might be cheaper to just buy the necessary moldings and sheet goods separately. If it's going to painted, the skill of the installer probably has a bigger effect on how good it looks than the material does.

Thanks for your reply.
The kit contains 4-24x24 panels, 5 stiles, Upper/Lower Rail, cap, and shoe trim. My take is to lay out the full length and adjust either by trimming one panel or all to make the appropriate fit. An 8ft kit costs b/w 110.00 (wall) and 150.00 (flat) and not sure how this compares to buying separately.

Here's another option that I used.

Put up your chair rail. Then used decorative molding over your sheet rock for the box look. Much cheaper and easier to do. And it looks really good.

Your trim box is determined by the length of each wall. When you have your wall measurements, you can figure out exactly how larger to make each box. The eye will not be able to tell if a box on one wall is a little smaller (one inch) that another wall.

Once you prime the wood and paint it, nobody will know.

Enjoy the journey.
eal51 in western CT

Thanks eal51 - You wouldn't happen to have a picture would you? Thanks again...