An interesting result popped up when I searched for RStudio cloud this morning: RStudio.cloud from RStudio itself.
"Kick the tires to your hearts delight - but don't plan on taking a cross-country trip just yet," the service warns on its home page.
I logged in using my existing shinyapps.io account, which the home page advises to do. If you don't use shinyapps.io, you can set up a new account there, or use Google or GitHub credentials.
The opening screen lets you create a project: