You could check with Jared from Bolt Woodworks boltwoodworks.com. I haven't worked with him personally, but he does custom woodwork and even incorporates recycled skateboards into his projects, so I bet he'd have some good ideas.
I asked @sarahward since she used to run Small Run Art. She suggested Annie’s Art and Frame in Ballard and said they might be able to handle it. I haven't used them personally, but they have some interesting (custom) projects on the web site. I also pinged a carpenter friend who promptly asked for a picture. :)
Annie's Art & Frame is GREAT!!! They are definitely my go to frame store. You may also want to check with Erin Guftason of ravennawooddesign.com I already mentioned this to her and she said she would love to chat with you and learn more about the project. Thank you @nathan for posting about Bolt Woodworks - I hadn't heard of Jared - his work looks incredible!