Batch Portable Installer?

There is an app called PortableApps Updater, that connects to the SF PortableApps site and allows you to select all the apps you need updated or installed.
It's soon to be released with the next version of the PortableApps Platform (the menu). It acts as a batch installer, because it serially downloads and installs all the apps you select.

While it is convenient, I would like it better if it included a download accelerator, or was able to use an existing one.

For most folks, the download of 40 apps or so is only done for initial setup. After that, they tend to only update one or two apps at a time as they become available.

If you are setting up multiple identical portable devices, you don't need to go through the whole install process independently on each. Once you set one up to your liking, just copy the whole thing to the other devices, and it will just work.
Same thing goes if you are migrating your existing portable apps to a new device - just copy and go!