00-swap-crypttab

cryptswap1 /dev/sdaX /dev/random swap,cipher=aes-cbc-essiv:sha256

01-swap-rc.local

# delayed autoenable:
(
        sleep 120;
        swapon /dev/mapper/cryptswap1
)&

02-largetmp-crypttab

largetmp1 /dev/sdaXX /dev/random tmp=ext4,cipher=aes-cbc-essiv:sha256 # not sure why tmp=ext4, this is likely reduntant

03-largetmp-mount

#!/bin/bash
DEV=/dev/mapper/largetmp1
if which zfs; then
	(
		#POOL=rpool
		POOL=largetmp
		sudo mkdir -p /tmp/large &&
		sudo modprobe zfs &&
		sudo zpool create -O mountpoint=none -O sync=disabled -O atime=off -O checksum=off -O setuid=off -O devices=off -o ashift=12 "$POOL" /dev/mapper/largetmp1 &&
		sudo zfs create "$POOL"/ROOT &&
		sudo zfs set atime=off "$POOL"/ROOT &&
		sudo zfs set mountpoint=/tmp/large "$POOL"/ROOT &&
		sudo zpool export "$POOL" &&
		sudo zpool import -d /dev/mapper -R / "$POOL" &&
		sudo chmod 1777 /tmp/large
		#zfs create -V 8G -b $(getconf PAGESIZE) \
		#      -o primarycache=metadata \
		#      -o com.sun:auto-snapshot=false largetmp/swap

	) || exit 2
else
	(
		sudo mkfs.ext4 "$DEV" -E lazy_itable_init -m 0 -O sparse_super &&
		sudo tune2fs -o journal_data_writeback "$DEV" &&
		sudo tune2fs -O ^has_journal "$DEV" &&
		sudo mkdir -p /tmp/large &&
		sudo mount /tmp/large &&
		sudo chmod 1777 /tmp/large
	) || exit 2
fi

Some reworked version: https://gist.github.com/v6ak/d5d49375d59cfae8e455