A question to experienced Pythoneers

[Rony]

Here's the story :
I've been hired by a company as a consultant to reorganise there
development department.
The actual situation is :
The manager of the development has been fired, main reason (what they
told me) is that they have big big troubles in keeping deadlines ! For
there last product, for which they estimated 3 man years of
development they had 9 months extra effort, and the product was
delivered a year to late.

I basicaly have 'carte blanche' :)

One of my plans is to introduce Python as development tool.
They mostly develop back-office software, and at the moment they do it
all in C with MFC.
Another new requirement they have, is that the new product should run
on Win & Mac.

So, my strategie would be :
- Use Python and wxpython for the GUI
- Develop critical routines in Pyrex or in C and make PYD's from it
which will be imported by the main Python programm.
- Distribute with py2exe on Win & py2app for Mac.

What do you think of this ?
Another point of attention is that the software isn't Open Source, it
is a commercial package. So protection of sources is important.
Now I know that anything can be decompiled, even C. The only question
is, how hard is it and how much effort must someone do to decompile
and retro engineer code to understand it.
I think by putting all program logic in Pyd files that I would be
quite secure ?
On a side note : Is it harder to decompile PYD files then PYC files ?

I allready had a meeting with the developpers and did a presentation
of python with wxwindow, mostly with an open source project where I
contribute to the development. They didn't see any big problems to
learn Python fast and they allready know C.

All opinions, advice here is welcome :)

Tia

Rony