[Taylor]

Here's a vote from Indiana. Southport High awards letters to veteran members - PM me and I'll give you a copy of our letter requirements. We mostly stole it from MOE - they've got a fantastic white paper on CD.
If the athletic director is against letters for non-sports, simply remind him that band members get letters too (as well as academic decathlon, academic super bowl, spell bowl, drama, speech team, and tons of other academic extracurriculars). Also, it helps to have a stringent letter-earning policy.
Good luck and Boiler Up!