I know of the Robison brothers. I don't care for Charlie too much, but Bruce sure can pen a tune! Angry All The Time is one of the most beautiful songs I've heard (even when Tim McGraw sings it

). I only know one other name that you mentioned, Adam Carroll. Unfortunately, I've not heard him, I've just heard the name and favorable comments.
My list of unknowns goes something like this:
1. Slaid Cleaves - born in Maine, but has lived in Austin for a number of years now. In the past 18 months he has really started developing a name for himself so he may not be all that "unknown". He is a great young talent!
2. Mark Erelli - Mark's out of Boston and just as genuine and nice a guy as you'll ever want to meet. I saw him open for Rodney Crowell a year ago in Philly and was totally blown away. I had to buy his two CDs on the spot. He just released his third which I have on order but not received yet. Anyone in New England who has the chance should check this guy out
3. Mary Gauthier (say: go-shay)- is from Nashville by way of Boston and Louisiana. She is also fairly new to me. I saw her open for Slaid a couple of times last year. Very impressive storyteller. Interesting songs. Great sense of humor. A lot of fun to see perform live.
4. Tim Flannery - I moved from New England to Southern California recently and was introduced to this guy's music. He is a coach and retired player for the San Diego Padres Baseball Club. During the season he writes songs while on the road with the team and records them and plays, mostly locally, during the off season. If you want to hear a CD that captivates you from start to finish with every single song, check out Pieces Of The Past.
5. Berkley Hart - Another San Diego based act. Jeff Berkley is a Kerrville Folk Festival winner and a well known talent in these parts and Calman Hart nicely rounds out the duo. Great guitar playing by both and awesome harmonies.
Any of these folks are well worth a listen if you have the chance!
Janice