Jon can build you Meta-42 based Home headphone amp w/ your choose of components. Jon built one for me recently and I'm very impressed by the amp and the builder. (With an upgraded power supply my amp ran $228 w/shipping inc. However, the price will be slightly more depending on what you wish to add to the base unit. Mine is a base unit.) Jon uses a Sennheiser headphone so he is very familiar w/their sound and would be able to build an amp to best match your tastes. To learn more, www.jmtaudio.com and www.head-fi.org.
Good luck! Bill
Good luck! Bill