AWS in theory has a product called service catalog that fills this role.
It's not super fun. Or at least my interactions with havn't been so great.
Good luck.
We've released an alpha version, with only one architecture, some days ago.
If you want to learn more, I've written a blog post: https://medium.com/revolv2/im-building-revolv-to-automate-cl...
When you say "'a la carte' consultancy", do you mean with a one-shot payment?
Do you think that the "user-friendly" features (deployment monitoring/rollback, CI on all branches, health monitoring...), that you can't have with Terraform only, are useful enough to ask for a recurring one?
People will pay you to build out their cloud infrastructure one feature at a time, or pick features off the cart as they want them (so maybe like an all you can eat cloud buffet?). There's a bonus to that too, iterative consulting is a great way to validate a tech stack for a problem domain before you figure out how to turn it into a recurring revenue source.
AWS for all its flaws is actually pretty good for this already, which I think is why it gets so popular with seed stage startups before they get locked in (plus the credits that they give out like candy...). I don't have to think about architecture, I google what aws cli command I need to set stuff up and move on with my life.
It's exactly what we've started to do: targeting startups in incubators.
DevOps people in early-stage startups are not very common, so it's seems safe to say that a Devops-as-a-service may be useful for them.