Automatic unique signature creator

[NotNite]

Right now with IDA's SigMaker-x64 you can place your cursor on a function and generate a signature for it (either directly or using callsite indirection):

A direct signature is available for the current address.
adding references
Added 9 references to the selected address.
added a total of 10 references.
[402ccd1e] Signature E8 ?? ?? ?? ?? 48 89 9E ?? ?? ?? ?? 48 89 5E 58  is a viable candidate for final evaluation.
[402e3d8e] Signature E8 ?? ?? ?? ?? 48 8B 1D ?? ?? ?? ?? 40 38 7B 08  is a viable candidate for final evaluation.
direct reference: [actual address in first opcode] E8 ?? ?? ?? ?? 48 89 9E ?? ?? ?? ?? 48 89 5E 58 

However, this plugin seems to only support creating a signature from a selection, which is not ideal if any part of the function changes (and doesn't use any callsite indirection at all). I'd like the ability to automatically generate a sig for a function that uniquely matches in the current executable.