SVG Displacement Map Filter

Hi,

does anyone have a clue how to use the filter texteditor to unleash the full potential of SVG filters?
Displacement mapping uses at least a source map telling the applied shape how to displace.
I can imagine these scenarios for the referring filter attributres that are quite useless:

1. optimum (but how to identify and access the IDs?)
in="internal ID of the filter target object"

in2="internal ID of a source object, symbol shape object"

2. url fetching – the hacky way (might face CORS issues)

in="target url"

in2="source url"

3. base64 encoding (Illustrator crashes) 

in="target image as data attrivute base64 encoded"

in2="source image as data attrivute base64 encoded"

4. a plugin that does not exist yet (select dropdown, SVG code editing, string replace....)
5. the native implementation of a alpha mask clone inspector:
Use an object (target) and the layer upon (filter source map) to apply the effect

Thank you.
Cheers

Jan