With the new addition of service hub it would be nice if you would revisit this idea.
With our QA and and dev teams using Trello it would be nice if Tickets created in the Service hub would automatically create a card in Trello.
The use case scenario that we envision is:
1. Ticket is created in Service Hub.
2. A corresponding card is created in a ‘Service Hub Incoming’ list in Trello
3. The URL of the Trello card is inserted automatically in the Service Hub ticket.
The above use case scenario represents the most basic integration and would be a good start.
As was mentioned above Zapier is NOT an option for us (and for many organizations) due to the costs and limitations on the amount of requests.