I have written a patch that makes network maps with lots of items look cleaner by reimplementing the way Zabbix frontend displays number of problems. The ideas behind this patch are
1) to make perception of large networks maps with lots of submaps and hosts easier by shortening labels under items;
2) IMHO for a submap or host group it is more useful to see the number of hosts with problems rather than the total number of fired triggers (problems) inside a submap.

Detailed description, screens and patch: http://www.zabbix.com/forum/showthread.php?p=72879