I'm a fan of clean code. I like my languages to be able to express what I'm trying to do, but I like the syntax to mirror that too.
For example, I work on a lot of programs in Objective-C for jailbroken iPhones, which patch other code using the method_setImplementation() function of the runtime. Or, in PyObjC, I have to use the syntax UIView.initWithFrame_(), which is also pretty awful and unreadable with the way the method names are structured. In both cases, the language does not support this in syntax. I've found three basic ways that this is done:

Insane macros. Take a look at this
"CaptainHook", it does what I'm
looking for in a usable way, but it
isn't quite clean and is a major
hack.
There's also "Logos", which
implements a very nice syntax, but is
written in Perl parsing my code with
a ton of regular expressions. This
scares me. I like the idea of adding
a %hook ClassName, but not by using
regular expressions to parse C or
Objective-C.
Finally, there is Cycript. This is an
extension to JavaScript which
interfaces with the Objective-C
runtime and allows you to use
Objective-C style code in your
JavaScript, and inject that into
other processes. This is likely the
cleanest as it actually uses a parser
for the JavaScript, but I'm not a
huge fan of that language in general.

Should, and how should, I create an extension to Python and Objective-C to allow me to do this? Is it worth writing a parser for my language to transform the syntax into something nicer, if it is only in a very specialized niche like this? Should I just live with the horrible syntax of the default Objective-C hooking or PyObjC?
If you don't have any experience in compiler or interpreter design my answer is an emphatic NO, it is one of the biggest challenges in computer science.
If you do have experience my answer shifts to "that is a really dumb idea."
Do you envision this becoming a large mature product that other people will want to use?  If you do than go ahead, otherwise it will just distract you from writing great applications.
Extending Python and Objective-C