I know some of you die-hard quilters will most likely faint at this but our group uses Curtain interlining!!!!!!!!!!!!!
I get it from this Ebay store
http://stores.ebay.co.uk/Roomserve-F...34Q2ec0Q2em322 it comes in Poly mix and cotton in different weights. Angelika Monks a well known quilter who does beautiful hand, and machine, quilter uses it a lot and I must agree with her, it's fab.