Not sure what you mean by "Mac interface". Does that mean the computer or just the WeatherCat software?
You might consider donating the hardware to a local school. They might not need or be able to use the "Mac interface". You might be able to take a tax deduction for the fair market value of the Vue. You'd want to ask your CPA, however, to see if that is worth the trouble.
You could also try posting at
Wx forum.net. They even have a 'sell/trade' forum,
For Sale/Wanted topics.