You're a season ticket holder and want to do something flashy to let the Mailman, Thurl, Mark, Johnny and the boys know you're with them through the playoffs. A telegram? Well, they've been done. All-occasion flowers don't quite seem right. And sending steroids would be illegal. I've got it. How 'bout a $50,000, 1,000-square-foot-sign? That's right. Why don't you order a yellow, purple and green Las Vegas-style neon sign fashioned in the shape of the team's logo, plus the team's slogan "We Will Rock You." And you'd probably ask to have your identity kept secret. Team owner Larry H. Miller said he's stumped about who sent the high-powered good wishes, installed Wednesday morning outside the Salt Palace. Joel LaSalle of General Display, the company that took just 10 days to design and deliver the gift, knows its origin. But he's not telling. Now, in all the excitement, did you remember a bow?