Well you cound make simple retextures, thats the easiest way
just download the free Software "Gimp" and search for tutorials. There are some specially for Oblivion.
okay figured out the screenshots so here are some of the retextured armors (only the cuirass and shields are my retex the rest is other peoples work) :
there first ones are based on these :
http://www.judgmentofparis.com/gallery/angerburg/teutonic01b.jpg
http://whitewraithe.files.wordpress.com/2010/01/knights_templar1.jpg
screenshots :
http://img59.imageshack.us/gal.php?g=screenshot0ub.png
http://img180.imageshack.us/i/screenshot3krq.png/
http://img826.imageshack.us/i/screenshot4sb.png/
http://img835.imageshack.us/i/screenshot7w.png/
the last 2 are based on the great movie kingdom of heaven :
http://www.southernswords.co.uk/images/SR-100941.jpg
http://www.southernswords.co.uk/images/SR-102113.jpg
screens :
http://img690.imageshack.us/f/screenshot9hi.png/
http://img256.imageshack.us/f/screenshot10g.png/
let me know what you think of them