Headphones--The Grado sound in a closed design?

As posted in another thread on closed headphones, I noticed the Phiaton MS 400s are well reviewed in the latest Stereophile survey.

Having just tried them, they do leak a bit of sound, but are detailed, revealing and efficient for use with a laptop or a portable device.

How much of a factor is size? Sennheiser HD280 Pro sound nice for closed cans. They are somewhat bulky, though, if you plan on using them in an active setting. For that purpose I suggest IEMs like Etymotic, etc. However, be aware that that kind of complete isolation can be annoying and in some cases dangerous.

Have custom wood covers made for your grados! I was drpping off a pair of headphones I sold to guy who was a real collector of phones and amps and I wanted to experience some of his cans to see what the best really were. He had a pair, I no longer recall the brand, but they may have been Grados that he had custom made wood covers for open backed headphones.

of all the phones he had, some in the $5K range, these were my favorites. I can't tell you more about his design for he closed caps, but they sounded awsome. If you really are interested in this, e-mail me and I can likely find his contact info. in old e-mails and get it for you.

Also, check out headfi, you will likely get the best advice there. Good luck