I've done roughly the same think from these website that has tons and tons of old radio shows. The latter link streams shows but it's not on demand streaming, as you know you can program Audacity when to start and stop recording.
This one sells shows for $7.00
http://www.originaloldradio.com/xxxframes.htmlThis site streams shows and sells recorded disc, most are $4.99
http://www.otrnow.com/Don't know about you but my time is worth more than $5. If you order complete show sets you can save 20%.