Bkay...as a long time Project Linus maker with over 80 quilts donated so far, any pattern will work for lap quilts. It isn't necessary to make all the blocks a pattern calls for, pick out one design for a block and follow those directions as many times as needed to achieve the required size. I have found that Villa Rosa Designs has many patterns with unique blocks you could pick out and use for lap quilts. Good luck and remeber to have fun!
I also like the Speedy Baby Quilt mentioned by IceBlossom!