1. How many tenants CloudPortal's server can manage? Are there any sizing information?
There's no hard limitation on the number of tenants CPBM can manage. The bottleneck is going to be your cloud resources. The system can easily manage 100,000 tenants, but having a cloud infrastructure that can handle the VM's, network, and storage for these 100,000 tenants is going to be the biggest challenge and that will have to be architected well.
2. Can customer enable HA for CloudPortal's server?
Two or more redundant CPBM servers can be set up to achieve a higher level of availability. This can be easily accomplished using a load balancer such as Apache HTTP or NetScaler. Assume "customer" means "cloud service provider" and not the CPBM end user.

3. Can administrator charge to create ticket in CloudPortal?
Presently, we cannot charge at the level of an individual ticket. But a notion of "Premium Support" can be sold through CPBM, as a Service Bundle. End-customers subscribing to this bundle can be provided access to raise tickets in a particular way. Depending on the use case, may require product customization.
4. Is CloudPortal user data same as CloudStack user data? In other words, I think CloudPortal user data is stored in CloudPortal's mysql, not CloudStack's mysql and is it managed individually?
Yes, user data of CPBM is stored in its own MySQL database and managed separately.
6. I know CloudPortal ticket service is tracked in web, is it notified by email as well?
This email notification will need to be triggered from the ticketing backend. For example, where a customer uses our productized integration with Salesforce.com Services Cloud, the email notification is sent from Salesforce.com. Some configurations will be required on the SFDC side.