Our company recently added a few of these:
http://www.saris.com/p-269-8000-stre....aspx?skinid=3

We now have space for about 30 bikes in our bike room. Just one of these might be a good way to start, for your location. They are easily expanded.

Prior to that, we just had simple heavy steel outdoor bike racks bolted to the concrete floor. Except that no one bothered to actually bolt them down, and they were constantly falling over when there was just one bike at the end of the rack. They work fine too though, if installed properly and if space isn't as much of an issue. I would just do this, if it were me, and spend the rest of the money on bonuses for the environmentally friendly bikers
http://www.saris.com/p-281-6200-seri....aspx?skinid=3