Chompsms will let you. I just sent out about 30 at 1 time yesterday.
Hmmmm, I just looked at the stock messaging app and it will let you. In the box where it says "TO" , out to the side is a tab. You just have to tap it each time to add another contact. Chompsms will let you select them all at 1 time though.
I don't know about the "reply all" but there is a way to send out to all of your contacts at once using Chompsms. In the box where it says "TO" hit the tab out beside it. At the top you will see 3 boxes. Choose the one that says "GROUPS". Then tap on "SYSTEM GROUP: MY CONTACTS". That will add everyone you have in your contacts list. Then just type out your message and hit send.