I could see teak working. It would be one of my least preferred materials, as my boat doesn't have any exterior wood, and I'd like to keep it that way.
Not having seen your boat and what you're trying to accomplish, I wonder if stainless steel would be a possibility. Some stock about 1/8" thick more or less. I had a local fabricator (non-marine) make up some stainless pieces for me to mount an auto pilot on my previous boat. It was under $100 as I recall. I gave them measured drawings (high school drafting class comes in handy now and then), and they made them. Had a couple 90 degree angles on one of the pieces.
You could use cardboard to make up a model and submit that to the fabricator. If I didn't have a local fabricator, or maybe even if I did, I would get in touch with Garhaeur (sp?) Marine and see if they could handle it. I've had them make replacement stanchions for me per my specs, and they were very reasonable. Considering they make line organizers and many other deck items, they might be a good source.
Also, with a stainless riser, you'd attach it to your deck like any other piece of hardware. Screws and sealer. 3M 4200 or if you can get your mits on some good butyl tape that'd be another option.