At what point is it recommended (or is it ever recommended) to move your resume away from a 1-page accomplishment focused resume to a longer, more detailed, or skills-based resume?
I suppose this could also be staged as a "managerial" resume vs a "individual contributor" resume.

Never
Never.
Accomplishments are what matters. Skills mean nothing unless translated into results. The better the results, the bigger the accomplishment.
Why is it different as an individual contributor vs manager? Managers have accomplishments too I hope.
Turn it on its head - if you show accomplishments, you must have the skills to support them.
If you are personally
If you are personally responsible for (as in VP or above) for profit and loss for $100 million in revenue, I think you could get away with it.
1 page resume
As someone who recently changed jobs, I like to think I graduated TO a 1 page resume.
After a grueling
After a grueling self-examination of all accomplishments I had listed, I am down to one page. I gotta say - it feels great. The impact is there. I know I will never be done tweaking it but I certainly feel better equipped.
Thanks for the input and I am also glad podcasts from 2005 are still online. I went back to the very first "Your Resume Stinks" and listened with fresh ears.
I can still hear, on almost every resume-related podcast: "never more than 1 page....unless you're Neil Armstrong...but then you don't need more than one line even if you are.."
Thanks again.