If you have multiple SQL Server instances already, have you considered an active/active arrangement rather than active/passive with failover?
xkoto (www.xkoto.com) is releasing support for replication of SQL Server using a pool architecture - our jdbc driver would route SQL statements to our GRIDSCALE virtual database which then load balances reads and does async replication on writes down to a pool (of 2, 3, or more) SQL Server instances. The pool is active/active so you don't need to manage failover.
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