Hello Lucas, Dave and Jennifer:
I am sure PRI will give you good information. They have much
experience now. Our conviction is that you don't require certification. We know, and so does PRI, that if you do excellent work then you will be recognised.
Permaculture is still young
enough for you to establish yourself as a designer, teacher, implementer etc without anything other than a
PDC. If you check our website you will see the video clip of
Bill Mollison saying, as he said from the beginning. "Go and do it".
Institutes are generally started by private individuals even if they are Not for
Profit, and so whatever standards they set, that's it. Sometimes you need to ask questions because there is no agreed equality of standards among Institutes and if there were it would require them all to meet and decide. No one controls
permaculture. It is like a web (dendrite structure) not like a branching pattern. There is no 'head'. So, there is really nothing to stop you starting your own. Ethically, put up your mission, ethics and way you will work and be accountable to your students, how you work, and public acceptance of criticism. There are probably other issues you would like to consider.
I don't know about USA but UK, Germany and Barcelona are permaculture members Institutes. There are surely others. There are also several pathways to a Diploma. Some are assignment based, others by merit - for those who have beavered away for years and require and deserve recognition.
Ideally an Institute fills a gap. Some deal more with Urban, the Mittel Alpen in Austria deals primary with plants and designs for middle Apline regions. Some are more rural. The Blue Mountains Permaculture Institute wants to support students in developing countries who do brilliant work but may not have English or money to pay.
Lucas, build your dream and do it well. If then you require certification then apply. There is much in learning and doing freely which is valuable. I haven't looked at the PRI requirements by the way.
Best wishes and go for it, all of you. You are really needed.