Trisquel: fully customizable installation using FDE
As requested by some other users, I did this test.
Requirements: Trisquel network installer or Live USB media, and one of the following networking condition (the last two options also require some network traffic fees):
1. Wired ethernet
2. Internal ath5k/ath9k (but not ath10k/ath11k)
3. USB ath9k-htc
4. WWAN modem that doesn't require non-free firmware
5. Android smart phone that supports USB tethering
If you already have the Live USB, you needn't to download the network installer. Just select the text mode installer after selecting language.
When you partition the hard disk, you'll need to create a /boot partition (for BIOS and MBR), or /boot and biosboot partitions (for BIOS and GPT), or /boot and /boot/efi partitions (for UEFI). Then create a partition used as physical volume for encryption using any available space.
Select "configure encrypted volumes" to set the password and make the encrypted volume usable.
Select "configure logical volumes" to set up volume groups (VG) and logical volumes (LV). You can customize all mountpoints.
The remaining installation processes are very straightforward and self explaining. You also have a chance to select services (including SSH) and desktop environments (mainly KDE and MATE).
The ubiquity-based installer (run under Live session) is rather inefficient. It basically extracts the squashfs image and then has to uninstall most of the language packages.