Hi,

Yes you can provide any SaaS using CPBM and, meter usage and bill customers. To achieve this you need to write the required connector for the SaaS using the CPBM connector SDK (more info available at: http://support.citrix.com/proddocs/topic/ccpb-20-map/ccpb-cssdk-develop-using-sdk-20-con.html)

After the SaaS connector added into CPBM you can configure it according;y.

Thanks,
Manish

I believe the components that you would require to enable SaaS (Saasify your applications) include:

a. XenApp to virtualize the application itself (Sounds like you already have this)
b. CloudPortal Services Manager (CPSM) - This would be the orchestration layer that provides the ability for your tenant admins to self provision these apps for their end users. Please note that apart from XenApp workloads, CPSM can also orchestrate the provisioning of other MS apps like Exchange, Sharept etc..
c. CloudPortal Business Manager (CPBM) - This would be the business portal - that enables you to create a service catalog of the different applications you want to publish to your tenants with the pricing policies tied to it. CPBM can also collect the uasge data from CPSM and invoice the customer accordingly. Please note that apart from CPSM applications (SaaS), you can also vend other cloud services like IaaS (CloudStack), PaaS (Partner PaaS platforms) from the CPBM Service Catalog.
d. The tenant end users can consume these applications using Reciever

Hope that helps.