Scubapro and beaver both have a product that sounds similar, a small pouch that contains an DSMB, with 9 metres of line attached.

Personally, I'm happier with a reel and seperate SMB, means I can deploy as and when I need to, or as per the skippers requirements. As suggested in other threads, you can clip them on to one of the billy's on your BC when not in use, it doesn't cause any probs or get in the way.