Not GP, but at my previous job we had something very similar. The form did offer options for a handful of variables (on-prem VMware vs EC2, vCPU, RAM, disk, OS/template, administrators, etc), but once submitted, the ticket went to the cloud/architecture team for review, who could adjust the inputted selections as well as configure things like networks, firewall rules, security groups, etc. Once approved, the automated workflow provisioned the server(s), firewall rules, security groups, etc and sent the details to the requestor.