CCR/SCR design query

Hi

I had a theortical query on CCR/SCR in Exchange 2007 that I was hoping someone could help me with.

Let's say I have a Main Office site in London, UK. The DR site is in Swindon, UK. There is a good WAN link between the two sites.

From what I understand, a good DR strategy for Exchange 2007 would be:

- Have a CCR/SCC cluster located in London with Hub Transport and CAS servers.
- Have an SCR target located in Swindon, also with Hub Transport and CAS servers.

However, how about this idea:

Have just one CCR cluster, but with one node in London and one node in Swindon (with HT/CAS in both locations).

Would this work? I can't see any reason why not and it would actually cut down on hardware expenditure? The amount of data replicated is still the same isn't it?

Secondly, is there actually any need to have a CAS server in the DR site?

Thirdly, wouldn't the CCR only method work better considering we'd need to upgrade to 2010 at some point, and 2010 does not support SCR/SCC?