Assuming that you plan to run all of this on a single machine, another interesting approach could be to just use shared memory among all processes and to do away with using Perl memory structures and instead use a fixed memory layout.

This makes some assumptions about the number of assets, markets and brokers, but basically imagine a (large) string indexed by fixed offsets where you write the (packed) prices to.

The downside is obviously the inflexibility between the server and clients, because you need to update them at once whenever a new market, asset or broker comes along.

If you use shared memory, you will get no backlog as it goes away when the last process is stopped. This may be an up- or downside.