Before things get out of hand - the Surface RT does not have a TPM chip (so I was told) - a mechanism for providing hardware-level encryption and key generation.
Some Enterprises implement VPN policies that require a TPM. However, Android phones (and I believe iPhones) do NOT have TPM either, yet support VPN connectivity.
So while there may be some implementations of remote connectivity that won't work due to the Surface hardware, the lack of a VPN client is really either a matter of MS not exposing the APIs to do it, and/or Cisco and Juniper not building a client.
As others have said, this is a new tablet and the chances one will be available is high - I hope.
Enough consumer pressure can move mountains. There is no reason the hardware, or the Windows RT OS would expressly prevent a VPN tunnel from being established, so it's either MS or the SW vendors that need to make this happen.
Perhaps someone should start and online petition?