Building Trades No Caste System To the Editor: In response to Michael Gavan’s letter (Letters, 11/00), I’m in complete agreement that high school students should complete their education and (at a minimum) sample college, or better yet, complete college. I take exception to his belief that to promote entry into the construction trades is to “encourage our future generations into a caste system….” I feel that if you could pull together a framing crew, interior or exterior trim crew, painting, roofing, drywall, stucco, masonry, or plumbing crew that would: 1) turn around prompt quotes you could stand behind, 2) show up as promised, 3) work professionally, and 4) service (punch out) your work promptly and without complaint, you would be considered