Thanks Andy for your reply, and also the link to all of your instructional videos which I find superior to anything else on the web!
In an effort to solve my problem, I came across the File>Delete Generated Event Files option in 10.1.3. First I deleted all render files, and the fcpbundle went from 106 to 48gigs. Next I deleted proxy files, and, lo and behold, the bundle file is now 1.99 gigs.
So, if proxy files take up nearly half the space as the original MXF files, as it appears, perhaps I don’t want or need proxy files anyway. I am using an IMac Late 2012 with 3.4Ghz Intel Core i7, and 24gb of memory, so perhaps there won’t be a noticeable speed penalty.