For the knitting savvy Twilight fan out there, I came across a yarn that is perfect for us.
Lorna's Laces makes a yarn called "Lion & Lamb" which features a colorway called..... "Twilight"! The yarn is a bit on the pricey side at $38 per 100 gram hank (approximately 205 yards). The yarn is 50% silk and 50% wool and is a varigrated purple colorway with dark, medium and light purples. It's very pretty, IMHO. Please note this is a colorway exclusive to Jimmy Beans Wool (yarn store).
If you are a bit more thrifty on your yarn purchases, fear not! This colorway is also offered by Lorna's Laces in Shepherd Sport yarn ($12.50/70 gram hank, 200 yards), Shepherd Worsted yarn ($20/114 gram hank, 225 yards), Shepherd Sock yarn ($24/100 gram hank, 435 yards), Sportmate yarn ($24/100 gram hank, 270 yards), Honor yarn ($24/100 gram hank, 275 yards) and Solemate yarn ($26/100 gram hank, 425 yards). For those who don't mind spending a bit more, this colorway is also offered in Helen's Laces yarn ($58/100 gram hank, 1250 yards).