Thanks for your reply. I wish for these firewalls to be stand-alone products.
I'm a bit confused still if this is possible; to present the pre-configured appliance types (3 types) as stand-alone products. If a customer orders type "Firewall A", blesta draws from the inventory of that firewall type (if inventory exists), and (here's the important bit) once the payment is approved, the customer is provided the unique login credentials which I have pre-created when we deployed the device, not credentials created by the customer.
The take-home point is that each device has unique login credentials preconfigured, thus I need to create pools of these appliances each as a product with unique attributes.
You clearly provide a huge amount of support here in the forum. Thanks for that effort.