zimmer family hitting max descriptor size

zimmer, one of our prolific relay operators, has recently started getting these complaints on his relays:

http status 400 ("Router descriptor was too large.") response from dirserver 204.13.164.118:80. Please correct

We talked to him and it isn't a 'huge exit policy' issue, it is a 'huge family' issue.

In the glorious future, we will have implemented proposal 321 and we won't have this size explosion from family entries. But we don't live in that future yet, so we need some workaround in the short term.