I have a python module that makes use of a huge dictionary global variable, currently I put the computation code in the top section, every first time import or reload of the mod
You can use a shelve to store your data on disc instead of loading the whole data into memory. So startup time will be very fast, but the trade-off will be slower access time.
Shelve will pickle the dict values too, but will do the (un)pickle not at startup for all the items, but only at access time for each item itself.