Currently, you can use an Absorption Radius Upgrade to increase the area of pickup for the Absorption Hopper, but sometimes I'd like to suck up stuff only in a 3x3x1 area.

For now, my workaround: The pack I'm playing also has the mod, Item Collectors. The Basic Item Collector from that mod lets you set the radius but not the offset; nonetheless turns out to be a good workaround for the lack of this here. (It's also a cheaper recipe.)