Joanne fabrics sells Velcro brand snag-free velcro in 3/4" by 36" pieces (or 19mm x 90cm for the metricly inclined). The package also says 1-piece design, so the 36" only gets you 18" of matable fastener length. Seems to me the package is around $3.50, so it's more expensive than regular 2-part velcro.
I found it in my local store, but I couldn't find it on-line. The SKU code for black is 75967 90666. White is 90667.