MySQL proxy to replication configuration
The new MySQL Router is one possible solution. Please take a look and let us know what you think! 

I'd love to hear what features you most want in future versions.

http://mysqlhighavailability.com/mysql-router-on-labs-the-newest-member-of-the-mysql-family/

http://mysqlhighavailability.com/easy-load-balancing-and-high-availability-using-mysql-router/