Thanks. Yes, that would have been my intention. However I reviewed the potential transplant Sony headphones a bit more and found that the headband would have been quite a bit more uncomfortable than the existing Fostex band, which really doesn't bother me. Also, the Fostex ear pads are really working out well for me. Since I installed a new "Y" cable into cups a bit less than a week ago, I was on the search for a small, black circular, plastic cap to apply some super glue to so I could cover the 3.5MM jack in the left ear cup. I found the specific item today at the auto parts store which ended up being a piece of plastic in a package of other components designed to hold the door skins onto a car door if you've ever removed them. I figure it will make my Fostex 'phones look a bit more finished after the cable re-work.
I'm now not so sure I'll look into a transplant project as I originally thought. My crystal ball is featuring a pair of Hifiman HE-5LE headphones in the vision. I'm ready to make the leap a but further. Though, i think I'll miss how the Fostex are essentially completely enclosed, which makes them a great pair of 'phones in many situations. The Hifiman, on the other hand, would have to essentially be relegated to home use as I wouldn't believe that I'd be carrying them to work daily as I do with the Fostex.
Some details to work on though. That's the fun of it.