I'll post my two cents here, i've been following this thread for a while now... A few months ago i stumbled upon an image of a pair of Smeggy's Thunderpants, I thought to myself man i wish i could build something like that!!! Upon further digging i found that Smeggy was gracious enough to reveal the basic plans for them. I planned out and built my own pair with lots of help from him and others on the thunderpants thread.
When i ordered my t50's, I listened to them for a few days completely stock and found them rather dull and not to my liking, the mids were nice but thats where it ended (this might be attributed to my amp, which was the asgard at the time) ... So i hacked the drivers out of them and put together my thunderpants, this took many hours of tweeking and running to random stores for odd parts. In the end, the result was a beautiful woodied T50rp. Beyond that it was a complete transformation in sonic characteristic compared to the stock configuration of the t50rp driver. You can eat the bass with a fork, the detailed creamy mids will put you into a trance, and the resolution of the treb keeps you engaged. And best of all it is all there in ONE package!!! These cans didnt shine until i drove them via a hybrid amp with gobs of current, thus if you have access to such amp it should pair nicely. I didnt like them with the valhalla either so im not sure a pure tube amp will do them justice either, they really like some push...
To put things into perspective, im selling my hd600 due to these modded t50 drivers
There is so much potential here, dont rule them out and keep tweaking your design as you will be rewarded! Ortho drivers respond very well to damping and tweaking so have at it! Or talk to ^ about a pair
Cheers H-fiers, M