Is there such a thing as an audio breakout box or extension that allows me to access (or move) the rear mounted jacks on my audio card to the front of my IBM Slimline 400 PC? As is, I pretty much have to lay on the desk and stand on my head to change from speaker system to headphones.
If your headphones are just headphones, I like using a DAC/Headphone AMP with line out for speaker, you can just keep both headphones and speakers connected and both work. Shut off speakers or turn them to 0 when using the headphones, turn down headphones when using speakers or leave them on all the time.
FX Audio DAC-6 is great for this and pretty cheap for the hardware you get. If you use a headset with a mic, you can either get a USB mic or use a DAC with a headphone in like the Shiit Fulla 3
This is how mine is setup, it'd the device on the left next to the speaker