I think that unless the video is absolutely riveting and the concept and editing are spot on, it would be hard for most people to sit through a 17 minute AMV. Especially one made from a single anime source, since there is a greater danger of using repeated scenes and filler to pad out the video. The only exception would be for long TV series, which Vampire Hunter D: Bloodlust is not.
I believe the general concensus is that videos should rarely go beyond the 6 minute mark. The sweet spot is probably about 3 to 4 minutes, at max possibly even 5. You can look at the average length of pop songs released today for guidance.
If you haven't read this post:
http://www.animemusicvideos.org/phpBB/v ... hp?t=67190 it has a
lengthy discussion about editing the songs for AMVs.
People that will watch this AMV will either do it for the song, in which severe editing will disappoint them, or fans of the anime which will may balk at a song that seemingly goes on forever and overstays it's welcome.
Ultimately, if you can sit through the finished video regardless of the length, and be critical of it (does it drag in parts, is it keeping it's concept throughout, etc.) then the video can be as long as it needs to be.