Currently hosts and templates can be made to include screens that are based on the hosts' or templates' items.
However, a screen based on LLD items in not possible.

I'd like a way to use item prototypes as input for a screen template. When using LLD to create items for all the ports in a switch, for instance, a screen can be created that will put all the traffic graphs for the switch ports in one overview.

The way I see the is working is the following:

-create a discovery rule with item protypes and graphs.
-create a new screen under the discovery rule with a name.
-since we can't predict the number of graphs we're going to get, we can set a fixed value for either the columns or rows (preferably chose able) the other will then expanded as needed. there will need to be a maximum amount of items that can be put in a screen.
-Then we can choose which itemprototype we would like to use to fill the screen. Since the total number of screen items is limited per screen, we can specify a regex to only match FastEthernet0/1 to FastEythernet0/9 for instance (regex: 0/[1-9]). We could then define another screen for FastEthernet0/10 to FastEthernet0/11 (regex: 0/1[1-9]), etc.
-You can view the screen as a normal template/host screen