First off, I prefer that this question be answered by a researcher who
has either direct knowledge/experience in the fields of profession I
am discussing, or is well acquainted with someone in the architectural
design and/or real estate development fields.

  Here goes: I have a BS in Mechanical Engineering from a 4-yr
ABET-accredited university. I am interested in crossing over/branching
out my structural design abilities into the architectural design
(private, not government) field. I have read a few online articles
about becoming a licensed architect, and they commonly state necessity
of completing a 4-yr undergraduate program in engineering or
architecture, and then (if I recall correctly) a 2-yr specialized
program in architectural design.

   Can I work in any capacity (and with any credibility) as an
unlicensed architect, having at the least a PE (Professional Engineer)
license in the state in which I work? Now, I understand that licensing
is done in order to keep public safety intact from incompetent
designers, but if I have an educational background in structural
design (Finite Element Analysis, Advanced Mechanics of Materials, etc)
from a BSME and a PE license, can I even get my foot in the door with
firms that do construction projects with relatively unique
architectural designs?

   Also, any information about the profitability of creating and
selling complete architectural design prints/works is helpful.
   -Are independent architectural designers/consultants successful financially?

   Any insight about the usefulness/practicality of courses taken in a
graduate degree or post-graduate program in architectural design. Do
they focus more on synthesis/design of structures in an
engineering/physics context than on aesthetics? Are some of the
courses really "artsy"?

   One last thing: Here are a few pages I skimmed over while examining
this career prospect:
http://www.texasarchitect.org/careers_becoming.php
http://architecture.about.com/cs/careers/f/homedesigner.htm

So I am informed about the Architect Registration Examination (ARE)
and the National Council of Building Design Certification (NCPBD),
insofar as what those two webpages contain.
   But, in all actuality, I am more interested in designing the
aesthetics of architectural works than doing the structural design
(which I have the knowledge to do).

   If I didn't quite connect the dots as to how the preceding adds up
to my overall question, just say; please be specific in your
Clarification Request. Thanks.