Following an issue I've encountered with SAM on our environment (Detailed here: HTTP monitor multiple IP addresses Dyamically,
or in summary: "you can't use HTTP Monitor in a template for several nodes which serve multiple sites using multiple IIS IP bindings"),
I've been intuitively looking for this macro, which apparently doesn't exist in SAM (yet...)
I think it will be a great time saver on some very common configurations, I know it will in my case...
The ${Node.All_IPAddresses} (or any better name you can come up with) should be similar to the ${IP} macro (as used in HTTP Monitor),
only instead of only holding the value of the node's main (or polled) IP Address - it should be holding an array of ALL the node's IP Addresses.
A good way to use a specific IP address from this array, would be to access it in a similar way to most systems: ${Node.All_IPAddresses[n]}
([n] being a [0... last] index value of IP Addresses in the array)
For example: assuming you need to set up a template with 3 HTTP Monitor components to assign for lets say, 50 web servers
and each HTTP Monitor should access a different site being served from a different IP on each web server,
Instead of manually overriding the default ${IP} macro and setting the wanted IP Address on your own for each site on each server (What are the templates for? 
),
You would simply use this in the HTTP Monitor URL:
http://${Node.All_IPAddresses[0]}:${PORT}/TheURLToMonitor.aspx for the first site
http://${Node.All_IPAddresses[1]}:${PORT}/TheURLToMonitor.aspx for the second site
http://${Node.All_IPAddresses[2]}:${PORT}/TheURLToMonitor.aspx for the third site
e voila, your job is done.
