Here is a project to implement an Arduino IDE in Python.http://freecode.com/projects/gnoduino
I've heard talk about a not-yet-mature project to do the same in C++ using wxWidgets. I can't find a link.
But speaking of C++ and wxWidgets, here's info about using Arduino on Code::Blocks.http://www.johnhenryshammer.com/WOW2/pagesHowTo/atmelPage.php#index
Here's info about using Qt Creator:http://www.meegoexperts.com/2011/09/qtcreator-arduino-development/
Late last year, at or shortly after Maker Faire in September, the Arduino Team showed a screenshot of an experiment to use Arduino with QT Designer, or maybe it was QT creator? I've not seen anything on that since then.
So far, I've not heard from many people actually using these. How useful they really are is a good question.
The 2 alternate IDE projects I have heard people actually using are based on Eclipse and Microsoft's Visual Studio. Obviously VS is closed source and Windows-only. Eclipse is still java based, and even far more resource intensive than Arduino!
The sad truth is the most usable and most widely used versions are suitable only for modern PCs with at least a gigabyte of RAM and fast processors.
How well any of this will work on a Raspberry Pi, even the Python version, is a very good question.
The RPi, I've recently learned, it ARMv6 instruction set, not the more modern (and more widely supported) ARMv7. The proprietary GPU is expected to perform quite well, but the ARM processor is very slow.
For example, from this article:http://www.pcpro.co.uk/reviews/desktops/374290/raspberry-pi-model-b
The CPU meter in the corner of the Debian screen is frequently maxed out for even the most conservative of applications, such as multitabbed web browsing. CPU-intensive applications are almost off limits: the GIMP art package took 1min 27secs just to load. In the SysBench CPU benchmark, the Model B took 107ms to complete one calculation of the purely synthetic prime number test; a mid-range desktop Core 2 Duo E8400 took only 0.85ms.
The sad truth is modern software development trades inefficient runtime for ease-of-programming. That trend has been with us for 20+ years as desktop computers have increased in performance. I really don't think the Raspberry Pi is going to reverse that trend.
When all the hype fades, much like OLPC, I believe RPi will find some nice uses... particularly for streaming HD video, and probably some projects were Arduino boards find uses today, but RPi's tremendously underpowered processor and limited memory are very likely to be a terrible disappointment for anyone hoping to run conventional desktop software.