A form offering is how you provide incident templates through the service catalog, you will never be able to create form offerings from service requests.
That doesn't make sense. According to the Admin online help...
Any business object that is part of the MyItem configuration (by default, incident, service request, and approval) can be made available through a form offering.
The help file is incorrect in that regard.
My items already has the relationships to ServiceReq, but the control is hard-coded and doesn't behave like Incident and Approval Vote Tracking.
A request offering is for Service Catalog items, a form offering is to allow you to present non-catalog items as offerings to the users through the service catalog. You cannot present a service catalog item as a form offering, how do you establish the template to use, or the parameters to fill in if they are in other tables? Service Requests spans multiple tables, a single form offering would not be able to account for all of the other tables involved. (ServiceReqTemplate, ServiceReqTemplateParam, etc)
Thank you for that explanation. I think that will help all of us.
So is it wise, or even possible to have a service request create another through its workflow - much like it can create other objects through its workflow?
It is possible to create a SR via a workflow. You'll have to have a block for each parameter and you will need to do some digging to get the right values for the template ID. There shouldn't be anything wrong to do it this way, but you'll want to make sure that everything still works as expected, like SLAs.