If you need a new dash fit, try this guy:
Name: Haneet Anand
Forum ID: hihaneet
Dealership: Speed & Sound
I got my Vento's dash fit from him, and it looks decent enough. The guy is good and helpful.
However, I think you're problem is more to do with the curved face of the dash fit and the straight faced HU. Try and find out if the after market dash fits are curved or not, the Scosche one you posted seems curved too.
Some pics would be helpful.