Yep definitely cavalier seats. Unfortunately, I find them far less comfortable than the HHR seats.
How about the "performance drivers seat" from the SS in all four positions?

 

That's what I am thinking

 

they are cavileer seats. i got these cause they were way more comfortable than the stock seats. i was also able to lower the seats front and back. the back seats have about 3-4 inches more leg room than stock. the back seats are from a 2 door so they fold down part way

 

here is an explanation of how i made the frame to hold these seats. use the pic posted before for reference.

for the frame, i just cut 2 pieces of 1x1 tubing the width of the 2 seats + about 4 inches to separate them. drill holes and bolt up the seats then i put a bar on each side to join the front and back. the rear tabs to mount it are angle iron with a slot in them. it needs to be a slot so you can loosen the rear bolts and slide this under. other wise you wont get the front tabs over the studs. the front mounts are just 2in flat bar. i set the frame on some 3/4" wood to space it and hold it level. then tack in the front and back tabs. thats where your tig will be nice. my mig is good for burning capet. a wet towl tent was the only way i could keep from burning the headliner and carpet. then just paint it to make it look good.

also remember to save the extra seat belt where you can find it. when i went to put my stock seats back in i couldn't find it. so now someone must share.