Some time back I carded some Blue Face Leicester, Merino, Silk and nylon.
I then plyed it with 100% cashmere from a recycled sweater. 
I bought the recycled cashmere from Jags Funky Fibers.
She does a great job of recycling thrift store sweaters.
The yarn I made is 4-ply (2 plys are the cashmere and the other 2 plys are my yarn).
I ended up with over 500 yards of some very nice and soft worsted weight yarn. The sample is knit on a size 6 needle.