If I make a custom action say using powershell to return a value, can I store that in a custom data field and later report on it? So as an example, LS does not return the amount of disk fragmentation, can I return that from a PS query and stick it in a custom field tied to each disk record?
You could theoretically create a script that's run as an asset action that 1) retrieves the data you're looking for 2) runs a database script to your Lansweeper database that updates a specific field for that asset, tblAssetCustom.Custom1-20 could be used for this.
We unfortunately cannot provide support in creating such advanced custom actions though.