A Rohde and Schwarz AMIQ might get the job done. Here's one for 3k:
http://www.valuetronics.com/Details.aspx?ProdID=8740)

It's got I and Q channel, so you can use it in stereo :)

14 bits, 16Msamples:
http://www.valuetronics.com/vt/assets/pdfs/R&S_AMIQ.PDF

It may be overkill for your problem, though...

Cheers

Markus

I have a WAV file which is a complex audio signal generated in PC
music software. I would like to play it back at an increased speed of
100 times the original.

For example, if the dominant frequency was 20KHz, the upper limit of
audio, at playback it would be 2MHz. That is as high as I need to go.

Obviously, this cannot be done, or output, from the PC alone. I assume
some type of programmable external hardware is required for storage
and sped-up playback.

What is the most straightforward ready made solution for this type of
application?

James Barlow