Versicolor - what kind of shop do you have?
There are two "vinyl" shops in my area that don't have space or the desire for metal or woodworking projects. So they (used to) farm it out to me.
If this is something that you would like to add to your repertoire, and make it profitable, seek out a "craftsman" in your immediate area who can make these for you. Meet with him/her in person to see what materials they can come up with, what is within their capabilities, time-frames, etc. The appropriate wood also MUST BE sealed, primed, and painted for extended periods of outdoor use with "minimal" maintenance. Buying from someone on the internet, to me, is taking a risk of what they use and how much care they put into their projects. Once it's in your hands, they are out of the equation for future anything. It's all on you.
Other than that, some jobs just aren't in everyone's wheelhouse and should be passed on.
Just my Dos Centavos here. All the best to you in your future endeavors.
John
Possible Resources:
Beautiful custom carved custom sign posts, finials and bases, for both single post and double post signs. Also decorative top and bottom cross-beams, all wood painted or stained to match sign colors.
www.artsignworks.com