What other ways are there to contact a domain owner for a seemingly unmonitored domain?
Subject: "Offer $$$$$ for transfer of Widget.info"
It was the only way I was able to get some people's attention.
I was able to engage some very private people in dialogue with that opening line. ;)
Other approaches: Phone (WhoIs, business, personal), letters containing endorsed checks with specific amounts with the payee blank (arriving on my legal letterhead).
The number of ways of connecting is only limited by your imagination and conviction/courage/craziness/etc.