Ciaran McCreesh <ciaran.mccreesh@googlemail.com> said:
> I realise this is a lost cause, but... Repositories are databases, so
> /var/db/ is your friend.
> 

i like it. Closely followed by /var/lib/layman...

wikipedia says in 
http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard

/var/lib/
  State information. Persistent data modified by programs as they run, 
e.g., databases, packaging system metadata, etc.

/var/layman i dislike due to this sentence in the FHS:

   "Applications must generally not add directories to the top level of 
/var. Such directories should only be added if they have some system-wide 
implication[...]"

IMHO layman does not qualify. i am not religious on these things, however.
kind regards
Thilo