I am building a whip using magus. The game we are playing has us at level 6, which is too low for me to get the feat which allows me to threaten with a whip. However, when holding a touch spell you threaten. Since you can deliver spells via your weapon with spell strike, this means that a magus using a whip and holding a touch spell (such as chill touch or shocking grasp) threatens all squares within 20 feet, correct?
http://www.d20pfsrd.com/gamemastering/combat
"Armed" Unarmed Attacks: Sometimes a character's or creature's unarmed attack counts as an armed attack. A monk, a character with the Improved Unarmed Strike feat, a spellcaster delivering a touch attack spell, and a creature with natural physical weapons all count as being armed (see natural attacks).