Broadband over cable benefits from the upcoming DOCSIS 3.0 standard. It enhances the user experience by expanding the downstream bandwidth to 160 Mbps. Approaching the bandwidth issue from the other side, namely the ISP's (i.e. dealing with efficiency), there are several options: fiber node splits, switched digital video technology, digital simulcasts, plant upgrades to 1 GHz spectrum, MPEG-4.
Also, two interesting companies are providing technology to MSOs.
First, Vyyo frees up bandwidth and had a number of equipment orders, as well as funding from Goldman Sachs and a board member appointment from another Wall Street firm. All this basically leading to a doubling of its share price.
Second, I stumbled upon this press release from PeerApp, which allows MSOs and ISPs to add P2P caching.