Lancer,
I used to role play quite a bit in a prior, long distance relationship. I'd send a "kit" box to my GF with detailed written or audio instructions (made in the day of cassette tapes and Dolby B) and the odd toy.
Sometimes, she'd be instructed to do what ever and then write to me about the experience. Others, I'd give her an "outline" of the scenario and then call late at night and "talk her through it".
While not as good as actually being there - it was pretty hot.
<And for any of you reading... no, I don't have any recordings - this was back in the day before I'd embraced my inner audio voyeur - although, I wish I had... man, was she hot AND vocal about it>
So... Lancer. If you can't find "captured" sound - why not go into production and make it?
If you want it on tape... you could find a voice changer (depending on the quality and your budget) and make it yourself. Heck, if you promise to record the proceedings - I'll make you a recording and email it to you (I have to chuckle though - thinking about the "bing" from film strips I saw in school as a kid.... "*bing* please return to missionary position... )
From what I recall, my GF liked the outline and phone scenario's the best... seems the tape didn't always go at the pace that she liked... sometimes too fast or a little too slow... on the phone, I could gauge her responsiveness and adjust from there (I did have the outline so I wasn't completely winging it... okay, I was winging it - but only with my left hand).
As far as a purely "instructional" audio - a light bondage scenario would probably fit the tape format better > more of an "authoriatrian" tone that doesn't need or care about her response.
If she's up for that give me a heads up and I'll see if I can help... If she wants to dive into the deep end, I've a million rollover minutes on my cell phone and free nights and weekends
Reg