Hey Fulcan and zukracer! I reached out to the team to get clarification around your question, as I was curious about this as well! Here's what I learned: Marriott doesn't have an "Around the World" package currently, but they do have Vacations by Marriott, which is where you can find all of the vacation packages that they currently offer. Here's a link to website, so you can check it out a bit more:
As zukracer mentioned, you can also call them at 877-483-7275, and see if they can help you find what you're looking for.
Fulcan (interesting, I typed mrmom9997 three times and fulcan keeps coming up, both with the same Dad of two profiles)
Whereas I'm sure they have probably also put out some great experiences as well, just be aware that Vacations by Marriott has had a few 'issues' with fellow Insiders, even this past year.
Best wishes toward a great trip
Thanks for all the feedback. Looks like I will use a combo of my Marriott points, Avios, United Air and another hotel chain reward points to paid for most of my 45 days hotel stay in my round the world trip - knowing that Marriott is not available in every country on this planet.