Im curios is technically a port to wp7 possible? if so maybe a community port can be made like the one for android.
Is a port possible? Yes.
Will there be a community driven port? Most probably.
Will it be possible to install applications on non-rooted devices? Maybe to unlikely.
Will it be possible to publish applications through the official store? Maybe to unlikely.
AFAIK Microsoft does not support C++ development on Windows Phone 7 (yet?). Having Qt with no way to build it or applications based on it makes the whole endevour rather pointless.
As far as I know (and I have seen) it is possible to run native code on rooted WP7 devices, although you are not allowed to on non-rooted devices. This is an artifical restriction, not a technical one. There are even "rumors":http://www.zdnet.com/blog/microsoft/mozilla-no-plans-to-release-firefox-for-windows-phone-7/5654?tag=wrapper;col1 that some applications will gain access to the native API officially - Adobe Flash as an example.
I do not know how far the native APIs have been stripped for WP7 but as it bases on Windows CE, which is supported by Qt, Qt might run "near-out-of-the-box".
From a business perspective one should make his own decision if it is really that wise for a new ecosystem that needs applications desperately to lock out hundreds of thousands of existing (Qt) applications just to push ones own proprietary technology. Microsoft does not just lock out Qt applications, it does lock out any popular native applications (Skype, Opera, Fennec, etc.).
So I wouldn't bet that this artificial restriction lasts forever. It currently leads to the curious situation the one can develop an application for "all" desktop (including desktop Windows) and mobile platforms using a single toolkit (maybe Qt) except WP7. Sounds very beneficial to WP7 and the WP7 ecosystem, which is quite healty anyways, to me!