Ikea is one place that sells all the hardware separately. Most other places sell it only with the fabric panels, and I don't know if it'd be possible to buy a "complete" system and retrofit the panels to insert your own fabric.

Generally the panels are supposed to overlap, so if you have a densely-woven fabric (and you might even need to line it with a room-darkening backing), you shouldn't see light coming through BETWEEN the panels.

I'll link to a photo on Ikea's website so you can see what its system looks like. (Unfortunately, Ikea doesn't sell these components online.)

Here is a link that might be useful: ikea's KVARTAL window treatment system

pammyfay--
Yes, I think that's exactly what I've been looking for--thank you! I'll make a trip to IKEA in Tampa and check it out. I hope I can do it in six panels on my very large windows.

Thank you, this is the question I've had. I saw them on HGTV but like you said hardware is only available at IKEA and not online.