I would really love to have this done in an portableapps.com version
As Bitwarden themself states it:
Solve your password management problems
The easiest and safest way for individuals, teams, and business organizations to store, share, and sync sensitive data.
App versions for desktop
Bitwarden is 100% open source software. The source code for Bitwarden is hosted on GitHub and everyone is free to review, audit, and contribute to the Bitwarden codebase.