Piggies will also be grateful for various cushions and beds.
My piggies have a fleece curtain that they love, it hangs over a single c&c grid. (That's if you have a c&c cage.)
You could also make them a hay holder bag. Some other ideas: a tent, a hammock, or a double tunnel that can fit two guinea pigs (Some that are shaped like a V to go in the corner of a cage, or an X shape.)
Her nick is "pastuszek" which means "little shepherd" :). I also sew, but lately I have much less time for this hobby, since I started working full time, nine to five.