RFC: new twitter_filter module

I'd like to create a new module that makes it easy to syndicate content from twitter and make it look good by linking to short urls, inlining images and showing videos. twitter_filter is focussed on processing content syndicated from twitter, rather than syndicating content to twitter (see twitter.module).

News Aggregator can be used to syndicate content from twitter:
http://www.alexstanhope.com/aggregator/categories/1

I'd like to create a module that:
* exports a bit.ly filter which turns bit.ly (short) URLs back into full urls
* replaces image links with inline img tags
* removes repeated text (e.g. my username in the above example) either manually or using Drupal string substitution
* invokes hook_filter to call his filter and any others that have been setup. This would allow [video:yyy] references to be turned into embeded youtube clips using the existing video_fiter module.
As I understand it, News Aggregator doesn't currently support filter.module (http://drupal.org/node/14104) although it may in D7.

It would work as part of the cron, much like News Aggregator which would continue to be responsible for fetching the content.

Comments and suggestions welcome. Although I've written several dozen modules, this is the first module I plan to contribute back to the community. My research has turned up no suitable alteratives. As such I'm posting the idea here for feedback, to avoid project duplication.

If this is new ground, please could someone in the know tell me how long I should wait before starting to code it?