I'm not aware of a sample that demonstrates how to parse a flat file using a stored procedure. However, this sample component may be helpful to you:
The community sample on CodePlex, RegEx Flat File Source, enables you to use an expression to extract values from a flat file. Specifically, the custom component "splits up a text file line by line, based on the groups defined in a regular expression
property."
This post on the SSIS Team blog provides an overview of the sample:
Regular Expression Flat File Source
The sample is avialble for download at
http://sqlsrvintegrationsrv.codeplex.com/releases/view/17644
Carla Sabotta