Controlling 5000 LED
The best approach is to place your LEDs in a 64x80 matrix. Since only 1 LED needs to be lit at any time you can use demultiplexers for both rows and columns. For the rows you want 1 line low, for the columns 1 line high.
One solution is to use ten 74HC138s for the rows, controlled by 7 address lines (2\$^6\$ &lt; 80 &lt; 2\$^7\$). You'll need some additional logic to derive the control inputs for each 74HC138 from this address. For the columns you'll need eight 74HC238s, which is similar to the 74HC138, but with its output active high. Here you need only 6 address lines (64 = 2\$^6\$). So you'll have a total of 13 address lines.  

Another approach is to use a CPLD. 13 address lines in, 64 columns + 80 rows out. That's 157 I/Os. Altera has a few MAX3000 devices that fit the bill.  

If you don't have a compact presentation for the LEDs like a synoptical panel, you may want to drive them with a higher current for better visibility. In that case you'll need extra transistors on the outputs.