Okay... a little more about the clients:
6 - Speak Spanish Only... and I have found a fellow in Argentina who will take care of these.
3 - High Availability Customers - For instance a credit union (bank). If they have a problem they need an answer quickly. I think I need someone who works during the USA working hours for these customers. These are the most difficult customers to find help for.
3 - ISPs/Hosting - One ISP is running SME as the email server for 2500 users. It's a cool implementation, but to support this you need to understand routing and firewalls because they do call for help... but it's only about the SME server 1/3 of the time. The other 2 are running BlueQuartz (formerly Cobalt RaQ servers with sendmail etc).
The rest are more flexible and include hardware stores, churches, venture capital companies, oil and gas, software dev, schools, manufacturing, architecture, travel agency, and sales. SME hardly ever breaks unless the sys. admin does something foolish and these sys admins are not foolish (anymore) All the hardware is DELL... so if there is a hardware failure call DELL and they can come out and fix it.
I do not do onsite visits. Instead, I'll talk the sys. admin through any hands on work.