Other people have. Look at a bunch of the Cavalli designs for examples. I'm not convinced he makes the best use of the LTP, with the way he likes to do asymmetrical loading, but they are great starting points for interesting stuff.
Anyways, the LTP is pretty awesome.
Lower gain than common cathode = lower miller capacitance = improved bandwidth.
Better PSRR than a common cathode.
Ooh, yea, balanced/differential outputs from a single ended (or balanced... ) input are pretty sweet too.
Really the only reasons NOT to use a LTP are that you cant afford (due to money, physical chassis space, or power supply power output) any extra tubes to make up for the reduced gain. In a hybrid headphone amp with the tubes you mentioned, the problem is almost never "I dont have enough gain" and since the amp is being designed properly from the start it is very easy to accommodate all the chassis space, heater current, and B+ current one could want.
A negative power supply to bring the tail back to (even if SS tail) is VERY nice, and adds to the price in an amp with a tube output stage but in a hybrid the power supply for the output stage can easily function as the negative rail for the input stage's CCS.
Edited by nikongod - 12/6/13 at 7:02pm