While on vacation I got the new QT 4.5 IDE working on my home computer, and it's very impressive. I think it's possible that it would be a good choice for development of IMT 2.0; it has:
- good graphics and drawing support, including SVG
- good XML support
- good Unicode support
- native compilation for Windows, OSX and Linux, as well as embedded Linux, S60 and Windows CE
- a new LGPL licence, which frees it up a bit
Drawbacks would be the need to learn C++ and QT (no small task), but that would be a good skillset to acquire for many future projects, I think.