If you save a destination device in your effects folder, you can use it as an insert.
It works well in modular. I have a patch with inserts for inputs and outputs. When it is not open, it looks disconnected. But it has routing inside.
It kind of works in 2448. The channel is muted, when there is nothing connected to the input, so you need a dummy input to activate the channel - kind of loosing the point then, but maybe your mind differs.
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If you save you source devices in your plug-ins folder, you can load them by right clicking the input tab. Works in 2448 and 1632. You get input loading without routing. It does get messy in the routing window, but it is nice for live bar users.
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You can have several instances of the same source devices loaded. This can help getting rid of cross wiring in the routing window.
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Remember: For the source and destination devices to work, you need to have the actual inputs/outputs loaded in your project. I have my ADAT source, SPDIF source, ASIO source, ASIO destination and Analog source open in a far corner of my routing window - out of view on my monitor.