belfour30;
If I understand your post correctly, what I believe you intend to do is to develop a "conceptual design" that would be used as a request for proposal. An ASME certified shop would review your conceptual design, develop final design and fabrication details for your review, fabricate and stamp the vessel.
If the above is your intention, yes this makes sense. You can use the above to narrow down the selection of material choices for the shop. Ultimately, the ASME certified shop is the one that will assume design responsibility and fabricate the item to ASME B&PV Code.