Handling content with slow change cycle, how do you do it?

Background (clarified):
We have several teams that provides service to customers. For each customer there are specific documents, information, etc.
Each team will need to work with their customers and the customers' content. We have a customers list, a services list and a teams list. The list of customers changes with a slow cycle, once per week or sometimes even slower.
Each team may provide one or more services to one or more customers. Each customer may receive one or more services, each service provided by one team.

We cannot use an OOB solution with connecting webpart for the 3 above lists.

Our solution was to provide each team with their team page. In the team page we have added the list of customers which they provide service to. The list of customers is styled using XSL-styling, so that the customers appear as a cloud of customer names. For some teams the cloud contains a few customers, for others a lot.

Question:
We see that the customer cloud may be slow in showing, using 1), when there are several to a lot of customers for a team. (team > services > customers)
1) We have considered caching the customers list for each team in the browser local storage and use CEWP to present the cloud using javascript. This solution gathers the team's services, uses those for a CamlQuery on the customers, thus getting all the team's customers.
2) We have considered generating the customer cloud as a static HTML file and then use CEWP to present the file. This solution would then need to be redone when customers changes.

Ps. we are running with Classical Experience only!

Have you done something similar? What did you do? What did you do differently?