sample:

def foo(a,b):
 print a,b

foo(1,2)
fa = foo%(1)
fa(2)
fab = foo%(1,2)
fab()

result

12
12
12

It's not entirely clear to me what you are proposing, but it looks like functools.partial[0].  Whatever it is, adding new syntax especially for it sounds highly unlikely. You might want to propose and discuss it on python-ideas though.

[0]: http://docs.python.org/library/functools.html#functools.partial

http://www.python.org/dev/peps/pep-0309/#note

--------------------------------------------------------------------

Abandoned Syntax Proposal
 
I originally suggested the syntax fn@(*args, **kw), meaning the same as partial(fn, *args, **kw).
 
The @ sign is used in some assembly languages to imply register indirection, and the use here is also a kind of indirection. f@(x) is not f(x), but a thing that becomes f(x) when you call it.
 
It was not well-received, so I have withdrawn this part of the proposal. In any case, @ has been taken for the new decorator syntax

--------------------------------------------------------------------


Maybe change '@' -> '%'

Using the func%(args) syntax is not possible because
fab = foo%(1,2)
is equivalent to
fab = foo.__mod__((1,2))

It might actually be possible to overload the % operator to make something that looks like your proposed syntax (without changing the actual Python syntax), but it still look hackish to me.
(We are also moving away from the % overload used by strings for the formatting in favor of the .format() method.)