Cross platform server based development

[Java script Dude]

Greetings,

I am currently at the dreaming phase of a new Open Source project to 
build a n-tier application that serves to simplify and unify data 
modeling at a level that would enable Open Source Product Data 
Management and Product Lifecycle Management systems.

Being a strong OSX advocate, I am really interested in using Objective-C 
along side Java, Python and/or Ruby. This application would be a 
headless server that would allow for developers to deploy custom web 
applications on top of the server through accessing custom query layers.

Ideally, the application would need to run on Windows :[, BSD and Linux. 
Although initial development would probably only be done on Free BSD 
only (personal preference)

My reasoning for looking at Objective-C and Python/Ruby is to enable 
extremely rapid development with less painful code and architecture 
re-work. Since such an application would be rather huge, clean, readable 
and robust code is a must.

[question] Is GNU Step geared to allow for such types of development?

Thanks,

Tim