Custom Apple Mail Stationery

They are just HTML files. Copy one of them and save it with a new name, then hack it up.

there is no way to modify the existing stationery. You can create your own though.
when you are creating an e-mail go to the file menu and click on "save as stationery". your current e-mail will be saved as custom stationery (it will be listed at the bottom of all available stationery). You can, for example, create an html file using your favorite html editor, open your file in safari and enter command+I. This will open a new message composition window with the html file embedded in it. You can save it as stationery.

sorry, I forgot to add. "save as stationery" is very buggy and will not display embedded images correctly (I've submitted a bug report about it a while back and it's still open).

To get around it you either have to manually edit the resulting stationery file or you can host your html file and pictures somewhere on the web and load that web page into Safari when saving as stationery. that way it will display correctly.

Also, the HTML in those stationery files (and the HTML that Apple mail output) is just horrible. I've complained to Apple about it and their response is that they have to support flaky e-mail clients from "other vendors" (wink, wink, you know who) that don't support modern HTML.

I doubt that is possible. Due to limitations in other, non-Apple mail programs, the stationery documents are very complicated and messy, they really do have to be coded by hand.

Stationery is fabulous for hard-copy correspondence. It is evil for e-mail.

Okay, I exaggerate. 🙂

As I've stated before on these forums, just because it looks good in your email client does not mean that it will display correctly in someone else's. Sometimes the "stationery" will be transmitted as an attachment. The recipient will get your email and an attachment. They will have to click on the attachment to see it. And they will see the "stationery" only. It would be like sending a postal letter with the words written on a plain white sheet of paper, and sending along with it a nice piece of colored stationery.

-fred