I needed a better LED holder so I made my own. To clarify this design works for TrackIR as well as OpenTrack etc software.
3pcs IR LEDs
1pcs resitor (or if you can't match the exact value combine two in parallel)
1pcs PTC fuse of at least 3xIf (for me 300mA).
4pcs thin wires (I used 26 AWG) I call these cables 1-4 in the description.
1pcs thin steel wire ~20cm
1pcs DC-power source with cable (or USB cable)
1pcs velcro strip
Using the LED Series array wizard (http://led.linear1.org/led.wiz) I find that for three LEDs (Vf=1.2-1.4 If=100mA) in series powered by 5 VDC results in me needing a resistor @8.2ohms
Using a parallel resistor calculator (http://www.sengpielaudio.com/calculator-paralresist.htm) and using the combination of resitsors I have at hand I get almost exactly 8.2ohms by using two resistors, 10 & 47ohms, in parallel.
I use a PTC fuse @ 300mA just in case to protect my power source (either a separate PSU or the motherboard if I use USB for power).
I've used the scematics in this link and built my setup according to it but with other components: http://myfreetrackheadset.blogspot.se/
Step 1. Pull the steel wire through the bottom LED opening all the way through the frame until it comes out on the back.
Step 2. Bend wire and attach cable 3&4, pull cable through the frame. Let the cable out at least 5cm so it won't get pulled into the frame when meesing with the other cables.
Step 3. Repeat step 1-2 but thrugh the top LED opening and cable 1&2.
Step 4. Push steel wire through the middle LED opening.
Step 5. Attach the ends of cable 2 & 3 and pull through the frame.
Step 6. Solder LEDs take note of the polarity and solder them in series. I used shrink tube to protect the pins from shorting.
Step 7. Push in the LEDs into the frame and pull carefully on cable 1 & 4 to get rid on uneccessary excess cable inside the frame.
Step 8. Solder resistor and fuse on positive cable.
Step 9. Insert power source cable into the cable through the pull release holes in the frame.
Step 10. Solder power cable onto cable 1 & 4, take note of the polarity.
Step 11. Push excess cable, resistor and fuse into the frame.
Step 12. Try out the LEDs with your mobile phone camera, if you bought narrow angle LEDs like me you might need to use the omni bouncers.
EDIT: I added a small part for a switch. A little tricky to fit everything but it it's do-able. Also added pictures on how I do it.