To answer your questions:
Q1. Is it possible to Have Multiple Selfservice portals in the system, where each each self service portal can have different set of fields while Submitting the Ticket?
>> Please stay tuned for this, it could soon be coming. Currently you can have only 2 flavors of the Self Service form -
1. The default with 2 fields Category & Description.
2. This is with any choice of fields you configure using Self Service field sets. This is referred as custom form.
From the Remedyforce administration tab -> Application settings ->Form Assignment -> Self Service: Service Request form, you can set the profiles who see the custom (field set) version or the default version.
Q2. Another one, is it possible to have different page layouts for Incidents and Service Requests. Using may be Record Types.
With the last release of Remedyforce ie Winter 14, You can create different layouts for Incidents to be used in Remedyforce Console (Staff users)
Is there any documentation on how this is done?