I bought enough veneer to try to cover a center channel if i ever get ambitious enough to try to build one. Haven't had time/money/drive for that yet.
Imaging was fantastic when i first set up these speakers in my livingroom so i wasn't planning on building a center at all. However, the wife insisted we reorganize the furniture and now the main couch is mis-aligned with the TV and speakers
The soundstage is no longer quite as anchored and i lost bass response because the rear-wall is now about 8-10 feet behind the cabinets. I'm now thinking that if i get a chance and some money i might try build a matching center. I was pointed to a variant of the Statements center channel with a sealed mid to compliment the Finalists. It was sort of a one-off design on a forum somewhere so i'll have to dig around to find it if i ever start a build.