I wouldn't do it in production environment at all. I was having in mind staging environment when you do big db structural change using one transaction.

Yep, it's worst-case scenario but it's working.

And sorry I didn't see SSC Veteran reply.

You can kill rollback only by doing that but you must have latest backup:

1. stop SQL engine

2. delete db and tlog files

3. start SQL engine

4. delete db

5. restore db