You can get easy to use rf modules, data in on the tx side and data out on the rx, howeverI think your right deciding to use infra red, dont bother makin a receiver, yo can get ready made modules with data out,I think tssop1738 is theone I've used, 5v in and data out with a pullip resistor, they need a good supply, a 100r resistor inline with +5v and a 100u cap in parallel should do it.
Directionality shouldnt be an issue, think about your remote for your telly, point in approximately the right direction and it works fine, as you say more leds gives you more o/p, if the room isnt totally black you'll be able to reflect the infra red off the walls.