Lynne,

If the school couldn't tell the odds between the jeans and trousers except on closer inspection, but have banned jeans; and if you have the skill to make trousers, may I suggest that you take the 'offending' jeans, open the french seam on the outside leg and remake it as a 'standard' seam, then remove the patch pockets, cut and insert linen/cotton internal pockets (using the removed patch pockets for the 'lead in', pocket edge binding and pocket flaps), you then no longer have jeans, but a pair of trousers in denim with a few rivets.

just a thought.

Tom (Walrus)