IPMI servers and related devices like Sun's LOM and HP's iLO have little to no storage space, perhaps a few MB of flash.

You can set up a limited number of users, like 16, and cannot store or access random data (i.e. you cannot use it like a 1GB USB drive). Of course, you could image that data, as there are tools under Linux etc. that let you read the IPMI / LOM / iLO information.