You probably need to check out the latest research from The 451 Group's open source practice. The study found the theory that customers want a "single throat to choke" when it comes to open source support is not supported by the evidence. That makes us wonder if it's hype promulgated by those who earn their keep by offering such support.
Only a minority of customers are really interested in a single support provider, according to Raven Zachary, who heads the analyst firm's open source practice. The 451 Group predicts that customers will increasingly look to their operating system vendors or application providers for that support. They may be on to something, since big players like IBM and HP are intent on increasing their open source support offerings.
Further, the study also found that large enterprises will move toward hiring their own open source experts and handling support efforts internally rather than looking to an outside vendor.
Maybe the success of companies like SpikeSource is more short-lived than we thought.