Oh My Gosh, Extreme House Makeover is one of my favorite too as well. Every time, I watch that show,
I gotta have a box of Kleenex next to me because it is definitely a tearjerker even though it means well. LOL
It's wonderful that you got to see the new house up close and to meet the rest of the crew. That was amazing and I am sure you will always keep that in your memories for the rest of your life. You can pass on that experience to others to make others feel special too.
You can be creative, say words that comes from your heart mostly and yet be subtle too. That will help with your creativity when submitting the request to ABC. Like others said, It doesn't hurt. Go for it and chase your dream!