How Can I Connect Two Sets of Computers Within My Home Office So There's No Cables On the Floor?
I would use powerline networking to link to a switch at the far end.
You can buy a pair of HomePlug units that plug into ordinary wall electric sockets. They will bridge the two ends of the room together without any cables lying on the floor.
Buy a couple of cheap switches, put them on either side of the room and plug in the PCs on that side. Run one cable neatly around the perimeter of the room, plug one end into your router and the other into the switch on the far side of the room. Connect the other switch that's on the same side as the router.
Well, you'll need another router for this, but this sounds pretty much like what dd-wrt client mode is designed to handle. You'll need a wireless router that supports the firmware, and you can connect the PCs on one side of the room to the ethernet ports on the router running in client mode (so you only need one device, and you can use conventional ethernet to connect those systems, rather than have multiple wireless adaptors), have the AP and other computers on the other side.
Get a pair of wireless access points that support Wireless Distribution System (WDS), use them to bridge the two locations on your network sans-wire.
There are pre-configured WLAN bridges that do all the work for you, like e.g. the Zyxel WAP5605. You attach them to a hub or router on either end of your setup.
There's another option if you have coax (cable TV) outlets in both locations; you can use MoCA adapters. MoCA sends Ethernet over coax without interfering with cable TV signals. I use this in my house to communicate between the first and third floors. Speed is comparable to a wired 100Mb connection (a little faster than powerline Ethernet, which I also use.)
Verizon FIOS routers implement MoCA, and used ones can usually be found on eBay for less than $50. They also include a 4-port switch. You would need one for both ends of your connection.
More info here:
http://www.avsforum.com/avs-vb/showthread.php?t=1145636