What you describe can be done with the Clusterboard and the Sopine modules (although network boot seems experimental). Not quite the same size or price point, but at least for clustering also much more convenient and performant.
Soon there should be also a 2nd module for it with a slower main chip but a AI accelerator unit. Although the Covind-19 situation seems to have delayed that product launch.
Edit: although I have to say that due to the small niche the Clusterboard is, the software is a bit lacking and the hardware has a few quirks that were never fixed it seems. I would love to see a new version with a faster module for it, but from the looks of it the Clusterboard as a product wasn't very successful for Pine64.
Soon there should be also a 2nd module for it with a slower main chip but a AI accelerator unit. Although the Covind-19 situation seems to have delayed that product launch.
Edit: although I have to say that due to the small niche the Clusterboard is, the software is a bit lacking and the hardware has a few quirks that were never fixed it seems. I would love to see a new version with a faster module for it, but from the looks of it the Clusterboard as a product wasn't very successful for Pine64.