On your latter two links the photographer was shooting before the "hot pixel" firmware fix, and he states he will give it another try - it would be nice to know how he made out. Another poster commented as follows:
"Hey man. Just updated the firmware and it fixed the issue for me. I mean you can still se it if the lens cap is on but it doesn't show up in reasonable situations. "
Anyhow last time I checked LifePixel, I was pleasantly surprised the cost for IR Conversion had dropped way down to $250 for the standard and $300 for the enhanced. I plan to convert my D300 this fall.