I finally received final word from RIM as to why in the new 6.0 operating system you cannot text more than 10 people in a group.
There response, was that the carriers decided they did no want their users to have the ability to text more than 10 people at a time. That the Group List function, should disable the ability to SMS more than 10.
What does this mean to you? This means that if you have a group of 30 friends and want to text them via your group when to get together, you will need to break your SMS to 3 groups of 10. This is very cumbersome and a waste of time, considering that the 5.0 operating system allows you to do this.
My recommendation, is to write to your character or hope that you will have a leaked 6.0 operating version that allows you to text more than 10 people at time in a large group.
I was out and saw someone with the new FLIP blackberry it seems on Sprint he is restricted to 100 people while the bold 9650 with OS6 is restricted to 10. On OS5 there are no restrictions, however it's not wise to do over 400-500 people.