Wow Colin - LOVE your spirits. As others have said - really neat idea your client has for surrounding his fire pit with them.
I am just working on small stuff now (hiking sticks and bark carvings) but someday I'd love to try the BIG stuff. I've been enamoured of the idea of live tree carving ever since I saw your article in WCI a ways back. We have a big old Maple tree next to our house that has started to rot out on the inside and will have to be taken down sometime in the next 5 years or so. Already lost one huge branch that just nicked the corner of the house. Yikes!
Anyway - I hope to put a big ole woodspirit in it to advertise my carving "business" - assuming of course I actually get to a point where people will buy them instead of just look at them quizzically.

That is also assuming that it hasn't rotted out too much in the trunk.
Thanks for sharing and I look forward to seeing the rest of your posts on this project.
Regards and admiration,
ChuckT