The RPI4 requires about double the power of the RPI3B+ to run optimally and so will only be available as an H model. The new design will be somewhat different than the current H model and will use a new, custom built PDU from PicoCluster.
The RPI3B+ will remain available in it's current forms as less expense and less powerful models.
The Advanced Kit and Assembled Cube come with the 4GB board. You can use any of the boards in the Starter Kit.
PicoCluster takes Raspberry PI to the next level by creating clusters of them to learn or teach beginning to very advanced computing principles. We sell clusters of 3, 5, 10 and 20 computers (called nodes), or you can build your own with either our Starter or Advanced kits!