This thread needs pictures. Here are some examples of lavalieres available from HJGREEK.COM (they're our official jeweler)
First, a less traditional one, but it's probably the more popular:
Here's the more traditional one (which I prefer, the heart shape thing is a little cheesy IMHO):
Here's the sweetheart pin, which as banditone and I were saying, at least in our chapters was reserved for the chapter's "White Rose" a/k/a sweetheart:
That website also has 2-3 different necklace options. I've never seen those personally. One of them resembles the badge so closely that I don't think Herff Jones (or whoever designed it) really had our tradition/rules in mind when it was designed.
But there ya go. Hope that helps.