OK, I was bored today and decided to whip something up. There's no GUI quite yet, so you have to enter commands manually.
Download the consolidated SWS extension here
Place a marker and edit the marker text such that it starts with !, followed by the ID of a command/action/macro. This command will be ran when the cursor crosses that marker. If you want to run more than one action, separate them with a space or create a custom action.
For example, this marker will cause the playback to jump to marker 2 when it crosses this marker:
Command IDs are available by scrolling to the right in the Actions ('?') dialog.
Time precision is ~50ms.