This is an option:
Press Right Ctrl+R keys and hold for 0,02 seconds and release
Begin Boolean Compare : [recording] Equals True
Set Boolean [recording] to False
Else
Set Boolean [recording] to True
End Condition - Exit when condition met
Set date [~nextSound] to [~nextSound] plus [10] seconds
Start Loop While : [recording] Equals True
Begin Date Compare : [~nextSound] Is Less Than Or Equals Current Date/Time
Play sound, '{VA_SOUNDS}\Recording Beep.wav' (and wait until it completes)
Set date [~nextSound] to [~nextSound] plus [10] seconds
End Condition
End Loop
When the command is triggered, it will press the key combination to stop or start recording(I'm assuming it's the same for both, otherwise you can add different keypresses to the condition instead), and if the loop isn't running it will set the variable to the running state and start the loop.
If the loop is already running, the variable will be set to the stopped state and the command will exit.
The command running the loop will stop the loop and exit.
There is something to consider here: I have the "Wait until sound completes before continuing command" option checked, which means that if you stop and start recording at the same time the sound is playing, two loops will run, and two sounds will play.
You can disable this option, but it will mean the 10 second delay will instead be 10 seconds minus the length of the sound; Pick your proverbial poison.
For the indicator light, if you're familiar with Arduino at all, you could buy a cheap clone, attach an LED(or use the internal one, if applicable), and control it via serial using an inline function. It's not as slick as something off the shelf, but you can't beat the price(and the API is pretty simple, which may not be true for a complete commercial product).
Do keep in mind that the above examples will be non-synchronized, meaning the VoiceAttack recording state and the actual OBS recording state can differ if a keypress doesn't go through(This is true for any solution relying on one-way communication, of course).