The method I selected was basically what I outlined in my question:
I write my beamer slides for class with the aspectratio=169 option. The projector in the room has a 4:3 aspect ratio but the letterboxing is not a noticeable issue for projection If anything it makes the slides easier to see since students in the back don't have the bottom of the screen cut off.
It is a noticeable issue for me, as I spend a lot of time rearranging slides laid out in 4:3. Also they've asked for much bigger font sizes than I normally use (72pt+ font size for the slide title?? I can't come anywhere near that close and have more than two words), but I'm working the best I can within their guidelines
For the post-production version with margins I use a pgfpages layout:
\pgfpagesdeclarelayout{NYU Open Ed margins}{}{%
\pgfpagesphysicalpageoptions{%
logical pages=1,%
physical height=7.5in,
physical width=10in
}
\pgfpageslogicalpageoptions{1}{%
scale=1.27,
center=\pgfpoint{5in}{4.25in}
}
}
That gives a 10in x 7.5in (4:3) slide with 1in margins on top, left, and right, and 2in on the bottom. After subtracting these margins, the printable region has aspect ratio 16:9—a pretty lucky coincidence.
Then I use PDF2Keynote (free) to convert the PDF, and open it in Keynote to save as PowerPoint.
I use beamer for all my teaching. The only time I might resort to Powerpoint is if I am hard pressed for time since it is easier to make corrections last minute. The fact that this happens less and less is probably because with time I grow more comfortable with Beamer. From a different angle, beamer forces you to think things through in advance.
For my graphics I use .jpg, .pdf and .png mixed in my presentations. Png is great for line graphics which it compresses very well. Since it is non-destructive, it does not compress photographs well so I use jpeg compression for such illustrations. Since I also work a lot with postscript output from for example Matlab, I convert the eps-output to pdf. All in all I find working with these graphics formats very easy. As you implicitly state working with LaTeX prevents cut and paste but I note that you use Photoshop in which case it is easy to cut from other documents and save as .png or .jpg. With Adobe Illustrator I am also able to extract postscript graphics out from (unlocked) pdfs which is very useful for teaching.
I am sure there are many other ways to get around moving graphics between applications but these work for me.
Best Answer
"beamer can export to PDF or PS", beamer doesn't export anything. It is a LaTeX class and LaTeX compiles the document to PDF (
pdflatex) or DVI (latex) which then is mostly converted to PS. There is of course nopowerpointlatex, so you will need to convert the PDF or PS somehow to a format PP can read, which would be RTF (Rich Text Format) or some Windows vector format like EMF or WMF. However, I would do it either with one or the other software. They do not mix well.