Hi James
Sorry, no, you can't do that.
The reason is that the stalled action emails need to be completely generic - if there was a variable such as @@/process_data/sales_sign_on@@
what would happen if a different process, one that doesn't have the sales_sign_on variable, stalls?
The good news is the LiveCycle ES does allow you to explicitly catch exceptions within the workflow, rather than relying on the generic exception handling capability. This means that you can catch any exceptions, and send your own email, with your own data in it, including custom process data, to whoever you want.
Howard
http://www.avoka.com