Here are some links with beautiful sets, and how can you complete them:
Scarlet Crusade Set (for all characters)
http://pt.wowhead.com/guide=953/so-you-want-to-join-the-scarlet-crusade#cloth
Mage sets made by transmog:
http://www.icy-veins.com/transmogrification-mage-cloth-sets-guide-wow
Vestments of profecy (cloth)
http://www.wowhead.com/transmog-set=597
More cloth sets:
http://disciplinaryaction.wordpress.com/2011/12/01/the-priest-mage-and-wizard-guide-to-transmogrification-an-illustrated-list-of-cloth-armor-sets/
Also, the http://disciplinaryaction.wordpress.com is an awesome site, and it talks not only about sets.
See most of the transmog sets already made:
http://www.wowhead.com/transmog-sets?filter=type=1;cl=8
