I don't know anyone selling them assembled. I do assemble a student's Mk IIIA kit in our Skunk Pharm Research BHO classes as a demonstration, and if you played your cards right, it might be yours, but if not, it also takes less than thirty minutes to assemble and pressure test one yourself.
Even if you aren't mechanically inclined, and assembly doesn't look intuitive, you will see how easy it is once you watch me do so in class. Some joints require Teflon taping, but the rest just assemble with Tri-clamps.
As for price for a complete unit, someone did journey to Portland to consult with me for free technical support once, after selling three complete packages for $8K each. That included the pumps, etc, which would have brought the total outlay for a parts kit and the same ancillaries at somewhere around $2500.
He did include a purdy cart with it, but the rest of the mark up was labor and profit.
While somewhat slack jawed and agape at the price, I'm also tongue in cheek, because both the buyer and seller walked away feeling like they got a good deal, which is how I define a good transaction.
I don't know of anyone offering my other designs in either kit or assembled form. There is a growing list of folks wanting a commercial Mk V and awaiting the test results from the prototype. I'm building the prototype for an associate for giggles, but it the waiting list looks attractive enough, there is a good chance that I can find a willing fabricator to supply the rest.
They won't be an angel supplier at near costs like Specialized Formulations with the Mk IIIA though, because the product is for commercial use, rather than mom and pops meds.