Brian from SRP Racing in NC makes them, I have got his throttle pedal cover (have had 2 actually, I started with the one that has 2 bumpouts for heel toe, and then went to the one that was a little wider but no bumpouts), and I just bought a pair of brake and clutch covers from them:
https://www.srpracing.com/pd-986-boxster-1996-2004-porsche-racing-pedals.cfm
Edit: here is a picture of them from Woody's build thread - these are the same style as the ones I recently bought.
https://986forum.com/forums/481406-post91.html