As a we agency, we use Zoho for us and implement Zoho One for our clients that also are service-providers. 

We don't sell inventory item, neither our clients.

But we sell bundles of services that would be easier to add as composite items. 

For instance, we want to make a bundle with "Website Development + Logotype creation + SEO Optimisation + Web Hosting" 

These are just services but I thik it would be logical to enable this functionnality