Yeah, that stuff ain't cheap!  I built this myself from 1 yd x 54" wide .74 oz cloth I ordered from BearPawwd fabrics at $35/yd and the double sided 3M tape them sell with it.  That and the hard parts from the original Instaflator someone commercially sells/sold.  I always thought the BA fill bag (Pumphouse) woefully undersize.

What model/size BA pad do you have? I might could be interested.  I got most of my BA pads from the REI attic sales (now called garage sales....) second hand. 

I'm interested to hear how the UL7 works for you.  Maybe I could help you out with a cuben fill bag? 

pd

....now where are the keys to that dang jet again.....