Ideally would be great to search on a chosen field (for us, country would be really useful as we have sales people in multiple countries and they need a quick way to find all their leads), and then be able to tag that set for rapid retrieval thereafter…

Absolutely vital to have this functionality… we often have multiple decision makers per opportunity and multiple invitees to events. An extension to this would be the ability to assign an email to multiple contacts – i.e. for Tactile to assign an email based on cc: as well as the to: field…