LW/AM/SW radio very cheap in laptop?

There’s another chance to get kids into radio…

If a high volume kids’ laptop had stereo “HD audio” ports available
(24-bit 192 kHz converters, 95 db input and 100 db output), how cheap
and small a circuit could you build onto that motherboard to provide
useful LW/AM radio reception? Could you use the left output channel
to tune, the right output channel to control the gain, and feed
the resulting filtered signal to a pair of input channels?

John