I am a long time intellij user.
The company where I work is likely to introduce Rational Team Concert to our department shortly. I went to the RTC demo and it looks like a reasonable product, built around Eclipse, but I would rather not give up using IntelliJ.
Does anyone have experience of using non-eclipse IDEs with RTC?
I would say that it could, it looks like IntelliJ offers an version control integration point as does the Jazz SCM component, but I am not familiar enough with IntelliJ to say for sure(looks like ClearCase is already on the list so they are adding support for vendors), I would think that without a full fledged integration where your Work Items are integrated into your development RTC starts to loose it's flair but may be not for your management :)
It seems that the answer is no.
Coexistence could cover many aspects; source code repository, Task lists, builds etc. But the first step would be integrating with source code repository and RTC uses something called Jazz.
There seems to be no available plugin nor plans for such.
This is going to be hard - you could configure IntelliJ to call the RTC scm commands, but this is not going to be that easy. I have heard of a company planning to build an integration, but not seen this myself (they might have finished this already). Company is called CM-Logic and is UK-based.