I found a 400w M59 HID ballast that is made in the F-can style. Here is a link to the product specs:

http://dyna-brite.com/Merchant2/merchant.m...egory_Code=FCAN

I haven't seen these used yet and was wondering if they had any benefits over a core and coil ballast.

The F-can's are coil ballasts... just encased in an f-can... If you notice the size of those things, you'll change your mind.