Ah LEGOS: Loved by kids everywhere, loathed by parents who inevitably and painfully step barefoot on the little plastic blocks/torture devices. The build-your-own-anything toy has gotten an adult-friendly homage thanks to EverBlock System, the New York-based company creating modular oversize plastic blocks that, similar to LEGO, can stack on top of each other to create, well...as much as you can imagine.
From their site: "EverBlock Systems was formed to make it easy for companies and people everywhere to build large-sized objects using a series of universal building blocks. We manufacture, sell and rent EverBlock globally and are building a world-wide network of agents, renters and distributors."
Sixteen colors and 10 available sizes, including full, half and quarter blocks, as well as five shelf sizes, can be put together every which way. Think temporary divider walls, creating a closet space where there wasn't one previously, building custom furniture like coffee tables, desks and bookshelves...basically the perfect solution for open lofts, small studios, garages and beyond. An additional plus: Everything is made of fully recyclable polypropylene.
The toy-meets-design fix may be a little pricey (each full-sized block—12"L x 6"W x 6"H—will run you $7.25, so building larger installations will certainly add up fast), but compared to the cost of a contractor, materials and construction, this temporary solution could be just what you're looking for.