Tablets too, maybe?

FTR: needs ItemStack capabilities which is not possible with the way tablet machines/components are currently handled in OC. Will look into that again at a later point, when I restructure that.

How would you handle if multiple components expose the same capability?

First one with hasCapability==true wins, pretty sure that's how it's for MCMP (which in this case is quite comparable), too.

Mcmp has sides, because they're still technically blocks. Items wouldn't
provide sides. Also, that sounds like a flaw in mcmp, unless there's a
order that makes sense.

Items wouldn't provide sides.

Tell that to whoever decided to use the same interface for ItemStacks >_> (yes, the capabilities for items also take an EnumFacing parameter).

I'd still suggest including a priority system for forwarding capabilities,
or not providing it at all. (Forwarding item capabilities when you have >1
item non-sided is fundamentally different to forwarding caps in a block
space.)