I currently host a web-based and SmartClient based application for this
customer on my stand-alone server which is colocated at a network operations
center in Orlando. My server is not currently part of any domain although I
could place a domain controller there at the NOC and join this application
server to that domain. This same customer is asking me to set up an office
network at their new location. I will be creating a domain for them
'FBSCI.COM'. There will be 8 hard wired workstations on this network and
about 30 laptop PC's for their 'in the field' representatives. I am not sure
if I will or should make these laptops members of the domain since the only
connectivity they share with the main office is through email they receive
in Outlook. (they use a 3rd party non-exchange based mail service provider).

I have two goals.
1) Currently the hosted application requires a separate login which using
SQL Server Authentication to validate against a database. I would like to
use NT pass-through authentication. Since there is no Active Directory
infrastructure in place currently, I need to figure out the best way to do
this. Should I create a domain on my colocated network then create a trust
between it and the new FBSCI.COM domain? Is that enough? Any details I
should be concerned about?

2) I would like to provide Exchange Server email/groupware as a hosted
service to this customer and other future customers. So whatever solution I
choose needs to take this into consideration as Exchange Server will also
require Active Directory based authentication and I would like to minimize
the amount of administrative overhead when adding/managing new mail users.