The bobbin winder on my 15-91 is very close to the body once you push the bobbin winder in place. The only spool that wasn't too long was an very old spool of Belding Corticelli silk buttonhole and button thread. The spool is 5/8" tall x 1'wide and holds 10 yards. It's a really tight fit without any hook & loop tape.
They still make wood spools. I've seen them in the wood findings section of craft stores and websites. Pet stores also have bird toys with colored spools.