Please provide several tracks (at least 8) available for purchase on
iTunes featuring a medieval chorus (Gregorian chants, Latin, religious
overtones preferred) in combination with an orchestra / symphony that
are very similar to tracks #1 and #2, "Burning the Past" and
"Crusaders" respectively, on the Kingdom of Heaven soundtrack.  You
can follow the link below to listen to song samples and get more
information regarding the album.

If there is diificulty finding similar tracks for purchase on iTunes,
I may also accept at least 5 CDs available for purchase through
traditional outlets.

http://www.amazon.com/exec/obidos/tg/detail/-/B00080EUN0/qid=1136227208/sr=8-3/ref=pd_bbs_3/104-7621413-6946319?v=glance&s=music&n=507846.

Not sure if this will help but have you tried Carmina Burana by Orff
http://www.amazon.com/exec/obidos/tg/detail/-/B00001ZSXC/qid=1136240344/sr=2-1/ref=pd_bbs_b_2_1/104-0325798-3066307?v=glance&s=music

 it's really only like 2 mintues or something of the first song thats
really good but it's the famous Gothic piece heard in Many movies.

I did purchase the CD through iTunes based on your recommendation,
although I'm still looking for something a little more stylistically
closer, in terms of the evenness of volume and tempo, to the tracks
mentioned above (?consistently calm and relaxing? may be appropriate).
 Thank you for your input.

Pay mrrohan-ga the money. You will not get more stylistically close
than the Carl Orff piece.

That's a good possibility.  It's not exactly what I was looking for,
but if that's the best answer, "mrrohan-ga" will get the payout.  I'm
going to leave the question open for a while though, with the hopes
that someone else knows of something that's a little more
?consistently calm and relaxing? while remaining stylistically close
to the tracks above.

Have you tried anything by Enya? She's pretty great, does a lot of
gregorian chanting and is very soothing and relaxing - I listen to it
just before I go to bed. Try "A day without Rain", "Paint the sky with
stars", or "Shepard Moons", to name a few. Or other albums of hers,
but I won't list them all here, I'll let you find exactly what fits
you.