Good question DJeX.
Essay, be warned:
There seems to be an aura of "evil" around trance I precieve among Christians, similar to
strip clubs and *gasp* heaven forbid,
tatoo parlors!!! 
(Seriously, I understand tatoo parlors tend to attract the ungodly but tatoos themselves aren't evil, and Jesus himself hung out in strip joints. Love the sinner, hate the sin.)
Trance, I think, connotates or suggests New Age spiritualism, an "opening of the mind" to higher enlightenment or somesuch. Indeed, a few songs I've run across do use this. For example, "Gamemaster" track of Paul Oakenfold's
Tranceport CD has a bit of spoken monolog by a woman that says "Embracing the godess energy within yourselves, will bring all of you to a new understanding and valuing of life..." and so forth. Awesome track, but now as a Christian, that small section of lyrics is a tad offensive.
Another aspect of trance that may seem anti-Christian is the drug use that often happens when trance is played at clubs and raves. I've been to many clubs and one rave. Although I did notice drug usage, it was fairly inconspicuous and none were offered to (or pushed on) me. I have great, drug-free times there. I go for the music.
But to answer your question, DJeX:
What I've discovered is that "Christian" music is
not a genre of music, for Christian music trancends genre (softrock, heavy metal, jazz, and in Andy Hunter's case, Techno). Christian music is not a musical genre, but a
topical genre.
Additionally, topics are predominantly expressed via lyrics, not style. If a song is about a guy losing his girlfriend, losing his job, and his dog dying, you might call it folk or bluegrass. If a song doesn't have lyrics, how can you tell what the
topic is? Can you name some Christian instrumentals? Unless the song is a remake of a known Christian song with the lyrics removed, or is an original instrumental song packaged with other Christian-lyricked songs, you can't tell!
Now take Techno. Techno is primarilly lyric-free. What then would make it inherently Christian?
[/END ESSAY] 
Hope you enjoyed. Despite the above, I also would like to know of more Christian techno. Checkin' out Andy Hunter now.