There are lots of options out there and they would even make a great Lala gift (my mother's grandma name) this mother's day. Mother's Day is Sunday, May 9th this year. Just in case you haven't started hinting yet...
My personal favorite (got that honey??) is from Swank Mommy. I love the modern look and that you can add a back plate with anything you like. For instance, the back could have a nickname, birthdate, or special quote from their favorite book....ANYTHING!
I also like that you can add different pendents as your family grows to create a cool layered necklace.
Another company that a lot of my 'boy mom' friends use is My Name Necklace. They are very cute and look great on. It makes a great gift for the expecting 'boy mom' too!