We also wanted the capability to associate contacts with each other, chart their reporting and relationship lines between the contacts, from inside of HubSpot. We were selling to large businesses, where understanding your key decision makers is critical.
We created OrgChartHub to solve this problem intially as an internal tool for ourselves. However now OrgChartHub is certified HubSpot App which works from within your HubSpot account, with no extra login required.
We have a free plan so you can test it out. I hope this helps?