Is it OK to solder wires on the LED, INFRARED LED, and PHOTOTRANSISTOR spots of the board so I can make an interative-something-else instead of an interactive LED *table* ? I could then solder the wires to the components somewhere else and make a interactive-3D thing instead of a table.

Er.. this may sound a bit confusing, so here's an example:
Imagine an interactive Chrismas tree (using the Interactive Led Table hiding under the tree)
If yes, is there a wire length limitation for this kind of project ?

Only Windell seems to answer my questions, so, thanks in adv. Windell !

Yes you can do it-- no problem at all. Nothing to worry about unless you use particularly long or thin wires. For regular easy to use wire, e.g., the 24-gauge wire found inside Cat-5 ethernet cable, you shouldn't have any worries, even if you put all of the components 10 feet away from the circuit board.

If you're going much longer than that or need to use much thinner wires, I can try and make specific suggestions if you let me know the details.