We're a small business of <50 employees that does 60+ trade shows per year. I feel the pain and am happy to see that you're tackling this.
We currently use Trello for task assignment, GCal for scheduling, Certify for T&E and Salesforce for lead tracking -- without a great way to measure ROI. I'd pay $100/mo for your enterprise plan if it integrated existing CRM and T&E systems.