Well I don't know of an integrated solution ! Do you ?
The P89LPC932 has a keyboard interrupt feature that will generate an interrupt if any enabled pin on P0 changes. Aad P0 does not HAVE to be connected to a keyboard. With the price od the 932 being as low as it is (<$1) I have started using it as a peripheral more and more.

Erik

PS In 'normal' applications I see no need for a keyboard interrupt, you want to scan every ~10ms anyhow. However, it is extremely useful in battery powered operations since it can wake up the processor from sleep.