This is with the Fedora 19 TC3 live image, booting off USB, on a UEFI system (MacBookAir5,2).

Start the installer, select language etc, proceed to disk selection.
Select main disk, press Done, decline reclaim and proceed to custom partitioning.

Make EFI System Partition (recognised as such including in filesystem type) mounted at /boot/efi.
Add /boot partition, ext2, primary partition, 2GB.
Add swap partition, LVM, 14GB, rename LVM VG and enable LVM (not per-partition) encryption.
Add root partition, XFS, LVM, automatic size.

Label all your partitions (other than the EFI system partition) appropriately.
Survey your domain with pleasure:
DATA
 swap 14GB nightslugs-swap
SYSTEM
 /boot 2GB sda4
 /boot/efi 200MB sda1
 / 195.16GB nightslugs-root

Click 'Done', observe that
Enter encryption passphrase, click 'Done' again.
'Error checking storage configuration' -> 'you have not selected a stage1 target device'. FFFFFFFUUUUUUUUUUUUUUUUUUUUUUUUU-

This occurs even if I explicitly add a biosboot partition, or when I have a separate /boot/grub which is VFAT, or pretty much anything, unless ...

If I have the root partition as a separate, unencrypted, non-LVM partition, and just confine home and swap to an encrypted LVM VG, then I'm OK.  So perhaps it just needs to check for an accessible /boot rather than an accessible root partition?