What I am trying to do is quite complex, so I figured I'd throw it out to a wider audience to see if anyone can find a flaw. What I am trying to do (as an MSP/VAR) is design a solution that will give multiple companies a session based remote desktop (companies that need to be kept completely seperate), using only a handful of servers. This is how I imagine it at the moment:

• CORE SERVER - Server 2012 Datacentre (All below are HyperV servers)
  Server1: Cloud-DC01 (Active Directory Domain Services for mycloud.local)
  Server2: Cloud-EX01 (Exchange Server 2010 running multi tenant mode)
  Server3: Cloud-SG01 (Remote Desktop Gateway)
• CORE SERVER 2 - Server 2012 Datacentre (All below are HyperV servers)
  Server1: Cloud-DC02 (Active Directory Domain Services for mycloud.local)
  Server2: Cloud-TS01 (Remote Desktop Session Host for Company A)
  Server3: Cloud-TS02 (Remote Desktop Session Host for Company B)
  Server4: Cloud-TS03 (Remote Desktop Session Host for Company C)

What I thought about doing was setting up each Organisation in their own OU (perhaps creating their OU structure based on the Excahnge 2010 tenant OU structure so the accounts are linked). Each company would get a Remote Desktop Session Host server that would also serve as a file server. This server would be seperated from the rest on its own range. The server Cloud-SG01 would have access to all these networks and route the traffic to the appropriate network when a client connects and authenticated so they are pushed onto the correct server (Based on session collections in 2012).

I won't lie this is something I have come up with quite quickly so there may well be something gapingly obvious that I am missing. Any feedback would be appreciated.