I don't mean these sorts of simple host-a-node services but something where you can run custom chains for your dev and testing. For example, this week I had to build a separate Polkadot chain for a client that had reduced governance term durations so they only took 5 minutes instead of 120 day and with a smaller council size so tests are easier to manage. This needs to run in CI so has to be in a position to spin up and tear down on command and the genesis block has to fund the appropriate accounts for testing. This could be pretty easily abstracted to a Web App for people to build this without needing to know how the underlying nodes operate, what to change, etc...