My Add-on Install & Upgrade add-on allows you to install/upgrade multiple add-ons with only one cache rebuild.
So you could either select a load of ZIP files which will then be extracted and copied across, have the XML files imported and finally do a single cache rebuild. Or if you prefer to upload the files yourself, you can do that bit manually like you normally would, and just upload multiple XML files which are then imported and finally a single cache rebuild occurs.