Creating a bootable USB drive from a distro split over two DVD ISOs

Solution 1:

No. Download the netinstall image. Create two partitions on the USB stick, write the netinstall image to the first, and copy the DVD ISOs to the second. When the installer prompts you as to which source you want to use, opt to perform a hard drive install and point it at the partition containing the DVD ISOs. The installer will then proceed to loop-mount the images and grab everything it needs in order to proceed.

Solution 2:

Unfortunately, you can't, for the reasons discussed in the comments. Your options are:

  1. Burn them onto two DVDs.
  2. Download the CD ISOs and use ISO2USB. (This is what I ended up doing, and it worked, unlike my other answer.)
  3. Download the net ISO and have the rest of the components you need be downloaded at the time of installation.