This is totally a PJ question but let me tell you ultimately it something Stuart would have to decide.
Here's why. The routes for Spectors are done with a pin-router system, by hand.
If you are familiar with a pin router, sorry to bore you with the details, but I'm going to share a brief description for anyone not familiar.
There's a table with a large pin (think the size of a good bolt) sticking up out of it. There's a drill press that's operated by a set of pedals. You press the pedal down (like the pedal of a car) and the drill lowers to the table. Let off the pedal, the drill head goes back up.
You then have to make a template for whatever you're doing. This template will have a track on the bottom of it that you create. That track will sit over the pin and once the drill is running, you'll press the pedal down lowering the high-speed drill bit and you'll move the template you've created (which is holding the bass guitar) along the track and this is how you get the route completed just right.
You may have to change the depth that the drill bit comes down (when you press the pedal). You may have to change drill bits (from course to fine, a larger diameter to smaller) several times in this process.
So back to the problem.
The Coda Body and the NS-Body use completely different templates for their body routes.
And to my best knowledge, Stuart hasn't created a template for the specific *unique shape of the Spector USA 9v circuit for anything BUT the NS-Body basses. So this means that a new template for the body route for the circuit would have to be created for the Coda body.
This can be a great undertaking as you might imagine.
So theoretically COULD you build a Coda and put a USA Spector 9vold circuit in it? Sure. That's IF a new pin router template is created to allow you to do so.
You can ask PJ and he may think it's worth asking Stuart... and Stuart may say "mmmmm... I'll think about it." or he may say, "No." And honestly PJ may just say "No" because he knows Stuart will say no because they've talked about it at some point.
The bottom line is that it's a major undertaking and the best success to see that it might happen would be if there's a demand for it... and you may be the first to have asked or you may be the 100th. And at some point a number of people who would want something like that is going to get large enough that Stuart and PJ would agree that the time and effort to develop a new Spector 9v Circuit pin router template for the Coda is worth doing.
I wanted to answer this question with all of the detail so you all can get a peek into what the NY Workshop is like.
It might seem like a simple thing to move something or change something... or because this model has it, why not do it on this model.
But these changes can become major feats of time management and work quickly.
This is the reality of building guitars by hand.
I'd encourage you to ask PJ and see what he says.
Which model are you using? It would seem most practical to buy the double bass bag for less cost than 2 bags. 
I'd consider them. 
