It should be noted that if you do put swap on SD that you can under no circumstance take the back cover off when the swap is mounted on the SD. When you do this the MMC is insta-umounted with respect to no man.

To remove the back cover without moving swap back to emmc is like pulling a RAM chip from a running PC but worse. I have destroyed entire SD cards and completely corrupted my emmc beyond backup menus help by doing this.

It believe it is entirely possible to create a 'swapon SD/swapoff SD' entry in power menu 'systemui.xml' just by adding a few lines just like phone/tablet mode button thing.