I'm not using the batch processor or the HTML export tools because I don't have jpegs for all my images, but all my raw files (DNGs) contain full size "developed" jpeg previews (which iMatch nicely picks up for its thumbnails!). I don't always want to generate jpegs for batch export when the embedded previews are more than sufficient, so, the option to use embedded previews for raw files would be a great feature for me.
The Batch Processor by default uses the cache image IMatch creates (on-demand or even temporary). Depending on your cache settings under Edit > Preferences > Cache, the cache files are created from the embedded previews in RAW files (this is the default because fastest method).
You can force the Batch Processor to use the full image by disabling the "use cache image" option on the Format and Size configuration page.
I think this request can be considered "done"