I find my old sheets everywhere, second hand stores, Goodwill, yard sales, my grandmother's attic. They are out there, you just need to look very, very closely. I will typically go into our local Goodwill in Ashland and Wooster once a month, more or less. And I will buy any sheet that looks remotely like it will work for something (as you can tell by my "sheet stash"):
I picked this sheet up (double bed size) for $2 today at Goodwill:
For the quilt, I cut up 6 different sheets into 10 1/2" squares. I cut the whole sheet up. I have 71 squares left (I used 54 squares on the quilt - so I have enough cut already to do 1 more quilt). The sheets were all various sizes. I backed this quilt in a sheet, and used a lightweight poly-cotton batting. I bound it in cotton, using strips from different fat quarters. All the sheets in this quilt were either $1 or $2 from Goodwill.
As you can see, it would work perfectly on Jessie's bed right now as is. But, she is a child who is not a quiet sleeper (note her current flip flop quilt laying beside the bed. So I think I want it 1 row wider so there is hopefully more to cover her with.
I made 2 for the kids as Christmas presents, here and here. These are both backed in flannel, with cotton binding. They are lap size and already both have seen lots of use.
The sheets have an added bonus, they can be made into pj pants. Jessie suffers from horrible eczema - to the point where her legs are an oozing mess. She cannot sleep in flannel pjs, fleece pjs or anything heavy. The sheets are perfect to make lounge pants, they don't stick to her legs when she sweats and I think they are helping us through these cold winter months with her eczema.
The sheet that I picked up today, I'm going to use it to back a sheet quilt for Jessie's bed, and then hopefully it will be big enough to make matching pillowcases for her bed. I'm on the hunt now for a fitted and flat sheet in the same floral color scheme for her bedding too. Somehow, it seems to me that the sheets I buy now, she will rip and shred while she sleeps, but the older ones will stand up to her tossing and turning (all her sheets for her bed - and I have 3 sets for both her and Tyler - have rips, tears and holes in them).
And yes, Warren, old superhero sheets would make a fantastic quilt (at least in my opinion) - a great reminder of days gone by......hehehe