Custom workflow steps in BCC / Prepending hostnames to images in media text

Question

We need to be able to prepend hostnames to image paths that are inside media internal text (MIT) items.
We have MITs that contain raw HTML from a 3rd party that get imported into Merchandizer.
Some of this HTML have <img> tags or reference images in inline <style> blocks, in the form of <img src="/foo/bar/xyz.png" alt="my image" /> or <style> .img { background-image: url(/foo/bar/xyz.png) } </style> respectively.
We need to be able to programmatically append imgX.mydomain.com to the image paths (where X is calculated by an existing component depending on some custom logic to point the relevant images to the correct web server cluster). Also, the 'img' portion may be 'imgprev' or 'imgstg' depending on the environment. eg: img1.mydomain.com/foo/bar/xyz.png for production & imgstg1.mydomain.com/foo/bar/xyz.png for staging.
We also need to be able to strip out the domains when the MITs are exported from Merchandizer.
My initial thoughts were to create a servlet filter with a custom response wrapper to do this, but this is additional overhead at request time we'd rather not have.
Is there some way we can create a custom workflow step to do this task, where the step would know which environment it was publishing to and programically append the necessary image path?
Any other suggested approaches welcome.
We are on 9.4.

Answer 1

http://www.adobe.com/cfusion/mmform/index.cfm?name=wishform