There were two offerings as far as "SunGrid" was concerned - either the public-facing 'retail' iteration powered by N1GE which was launched as network.com ("$1 per CPU per hour!") and also a B2B commercial version which offered a lot more flexibility, i.e run your Linux distribution on Sun's hardware. The latter was built at scale using AMD Opteron-based SunFire V20z's for compute, for example.

The former certainly suffered from platform constraints and a fairly rigid 'stack', but the latter was far more flexible and various teams within Sun worked closely with several potential customers on the proof of concept. Unfortunately this fell apart thanks mainly due to the commercials and some concerns with how the platform was configured within the context of security and ensuring appropriate segregation of data.