Maybe it’s too soon for the good news to show up on Covad’s bottom line, but a report out today from In-Stat should cheer Covad strategists, since it claims that hosted Voice over IP services “will continue to experience dynamic growth over the next few years,” reaching the $2 billion mark by 2010.

Studies are studies, and it’s easy to point the graph up and to the right when you don’t have to close the sale. But there does seem to be a kernel of sense in the idea that very small businesses — In-Stat calls 20- to 50-seat deployments the sweet spot — would turn to an outsourced or hosted VoIP model, rather than looking for in-house expertise, software and infrastructure.

While Covad CEO Charlie Hoffman said earlier this year that VoIP overall and for small-biz specifically “isn’t yet at that hockey-stick growth phase,” he did say that small businesses are historically underserved, even though they represent a big part of the overall economic pie. And as providers add more functionality (like the fax-over-IP feature that Packet8 announced at CES), it sounds reasonable that small businesses looking to add functionality to their phones or lower their telephony costs would look first at a hosted VoIP model.