Currently to my knowledge MPT has no simple way of exporting songs that loop with a fadeout without adding a fadeout pattern to the module itself. Therefore, I think it would be nice to have the option when rendering to MP3/WAV/etc to set an optional fadeout length for the export. I haven't extensively thought through what it could look like UI-wise, but maybe a checkbox + input field similar to the "Limit song length" field? So for example I would be able to choose "play entire song 2 times" and select a fadeout length of 10 seconds and I'd end up with a render that plays the full loop twice and then 10 seconds of a third loop fading out.