We have mentioned this before, but with some nice examples on offer on eBay right now, the Ladderax modular shelving and storage systems are worth another look.
Ladderax as a 'look' has never been so hot. A midcentury storage system that was popular 40 or 50 years back, it is now inspiring both modern-day designers and the high street. Just check out this Matthew Hilton for Case modular shelving for an example of that.
But originals have the period charm too and are still in plentiful supply. Just buy the 'ladders' and fix your storage units and shelving within, then add more units and ladders to fill the space you have.
In fact, just check the full selection on eBay if you are interested. There are around 40 pieces there right now – and more appear each week.