Hi Josh.
Yes, there is interest. In fact, I recently fixed some base issues to get our exporter going with the latest JavaFX. That was done in fair bit due to end user contact... that is, people who wanted to be using it asked about getting things fixed and gave some feedback, testing, etc.
Excellent!
Some user used Twitter to point out this blog post: http://lucasjordan.blogspot.com/2009/06/inkscape-and-javafx-almost-there.htm...
The corresponding initial fixes were under bug # 253869 https://bugs.launchpad.net/inkscape/+bug/253869
Using the test case from that blog post, I also figured out what the problem with the gradients are. If someone can enter specific bugs for those then I can probably get them fixed for 0.47.
And in regards to .FXZ export itself there is definite interest. I think as a packaged-up container format there are some nice things that can be leveraged post 0.47. Among other things we've been wanting to add in an internal "media manager" to handle external files (bitmap images, ICC profiles, style sheets, etc). Including conceptual needs and such for .FXZ will probably help with the general solution also.
(BTW, I noticed Martin Brehovsky commented on that bug after it was fixed)
Yes. Martin would be one of those aforementioned overworked engineers. :)
So it definitely sounds like there is interest. How can I help you?
- J