I like the concept of the change, but this would be better in the cache_memoize function in Djblets (djblets/util/misc.py).
Honor memcached key size constraints
Review Request #975 — Created Aug. 19, 2009 and discarded
RB will happily try to enter keys into memcached that exceed memcached's key size constraint (250 bytes). This patch should correct this.
Runs flawlessly on a local RB installation.