Can I create another portal home from the end after I've lost mine?

Short answer: NO.

Once you break your portal blocks, there's no going back, unless you spawn another enderdragon (to spawn a portal upon death), place the necessary blocks yourself (via TMI (aka Too Many Items)), but no other solutions. Note, nether portals also do not work here, as they cannot take you back as well.

Unless you plan to use external 3rd party programs, as fredley mentioned, you cannot create a portal home.

Long answer: YES

What you will need to do is use MCEdit to place a new End Portal.

Here is a schematic. You'll need to import it with MCEdit and place it, and it should allow you to leave the End.

If you have cheat mode enabled you can /give <yourself> 119 which is the end portal which will transport you back to your spawn point in the overworld