I've been doing just that over the last few days.
If you use the HP Drive Key Boot Utility you can add multipule disk images to the usb drive - no need to partition it.

I've created some more advanced menus with the software below:

Use hexplorer to edit menu.msg and customise the boot screens and menus.
RawWrite to extract images from floppy disks
Virtual Floppy Drive to edit disk images without writing them to floppy