It's the solution of choice for the Launcher - try setting your Launcher icon size to 64 and it will happily scale Thunderbird up that level. Surely a touch of anti-aliasing could appease the nay sayers...
It just seems like a better, more unified (pun intended) solution than having one tiny icon in the row.
My last idea on this (before I go on holiday) is to have a stock mail icon that is used where no suitable sized icon exists for the preferred client.
It's the solution of choice for the Launcher - try setting your Launcher icon size to 64 and it will happily scale Thunderbird up that level. Surely a touch of anti-aliasing could appease the nay sayers...
It just seems like a better, more unified (pun intended) solution than having one tiny icon in the row.
My last idea on this (before I go on holiday) is to have a stock mail icon that is used where no suitable sized icon exists for the preferred client.