Resources & Acknowledgements
There are many useful Beach Boys reference sites out their - particularly useful have been Andrew Doe's Bellagio site and Beach Boys Legacy.
Three forums may be of interest - Steve Hoffman's forum for more general rock chat, and the Smiley Smile and Pet Sounds forums for Beach Boys chat.
Also useful more generally was Wikipedia and Discogs, so thanks to anyone who contributes to those sites.
Thanks to the users at the Pet Sounds forums who gave me a large list of covers to start with.
Special thanks to Dogear for his list on 45cat and JK for constantly finding interesting non-English covers.
And finally, thanks to those who have emailed me with covers to add.