Haha', great minds think alike...

I've just this second been trying to search for a Thunderbird
Extension, which will automatically read out aloud, incoming Mail. I
hope it supports SAPI 5 voices.

I am also using Thunderbird as an RSS reader, which scans for new
feeds every 10 minutes. So hopefully, it will also be able to read
them out for me too (as long as 'Show the article summary instead of
loading the web page' is Ticked of course).

Good Luck with it anyway!