This application technaclly is portable. It, however, was not intended for portable use. It was made for downloading programs and installing them automatically. It currently has a number of programs from portableapps.com and a few other apps.
http://sourceforge.net/projects/pa-install
Note: this is open source/MITed.
Features:
Auto-Update: I can update the application list on my site and it will get the new apps. This can be disabled by deleting the updateiniurl key (or by setting it to an empty string).
Direct Copy: Dont't extract, copy.
Batch Command: run a batch command when the install is completed (to rename files, delete files, create files, etc.) [Note: this will now prompt before executing]
7-Zip and Universal Extractor: PAI Extracts archives using 7-Zip by default installation. UniExtract can be used instead.