MAC Fake with IPoIB

Recently we have seen several applications that required 
An equivalent to Ethernet MAC faking, in order to implement fail-over
between two nodes, Currently the way IB is implemented you cannot
implement such a capability with IPoIB, and a node cannot take over
another node's MAC (GID/LID+QPN).

Few possible solutions can be:

1. Implement gratuities ARP's 
That solves the problems for only some of the applications, and cannot
help in cases with Active/Active, >2 configurations
Or another example is that it won't work with VRRP 
So it doesn't solve the problem 

2. Define that an IPoIB driver should also listen on GID_out traps, and
clear those GID's from its ARP cache when they go down.
This can be used if it is possible to bring the port down in case of a
failure (or make the SM issue the GID_out trap)

3. require IPoIB drivers to support the UNARP RFC (RFC 1868), this
allows a node (taking over) to ask a remote node to clear certain ARP
entries 
There is precedence to using UNARP in IP over SONET/SDH (RFC 2176) for
the same reasons 

4. any other methods you guys can come up with 

Your thoughts/suggestions ? 

Yaron