Slightly OT: best alternative to mod_perl when perl can't be used

[snacktime <sn...@gmail.com>]

I'm working on what will for the most part be an open source project,
but one layer of the application needs to be closed source (but still
free).  This layer implements an api that is covered under a contract
which limits distribution to object code only.
The application is an open source payment system.  The layer that
needs to be distributed in object form only are the parts that connect
to the bank networks themselves.  One or two of the bank networks
might let me release the source, but not likely at this point.  And in
any case, the source for this layer of the application is not
something you want people messing with, and there very few reasons why
someone would ever need to modify it.

There are basically 3 layers to the application.  One is the outward
facing gateway that transactions get submitted to.  This runs under
mod_perl.  The second layer contains the processing modules for each
bank network.  Layer one communicates with layer two via the standard
CGI interface, although this could be changed rather easily.   Layer
three is the administrative/reporting interface.
All three layers can run on the same or separate servers, usually the
later for security/reliability/legal reasons.

After evaluating several options, my first choice at this point is to
go with python using mod_python for layer two.    It fits in nicely
with the apache/cgi framework, and should be fast enough.  I also
considered Java and Ruby.  My gut feeling is that Java would end up
adding more complexity than is desired.  As for Ruby, it might work
just great but I'm not sure what advantages it would have over Python,
and I'm not familiar with it so that entails another learning curve I
don't really want to go through.

Anyone have any other suggestions?