A recent poll has Cornyn up 51-36, Perry up 55-37, and Dewhurst up 50-40.
What congressional race are you talking about you think the Democrat's have sewn up? Both of the new seats will go GOP and the only remotely competitive one is TX-23 (Bonilla vs. Cuellar) and I don't see Bonilla losing (for many reasons I could share). I think the appointment of Texan Tony Garza as Ambassador to Mexico will help the GOP in TX, too.