It is not currently possible to edit/create new templates,
however that is something we are looking into making possible in
I generally suggest storing things that don't fit into a
template in secure notes, but with iCloud, for example, the fields
are exactly the same as they would be for MobileMe, so you can
probably get away with using the MobileMe template.
Buster, it's true that customisable templates have been a long
time coming, sadly we hit some major roadblocks with them just
before the 1Password 3 days. We're still hoping we can add this to
1Password in the future but we just can't promise when.