Actually not necessarily the HTC Hd2 fits the bill when it comes to a hackable geek device sure it doesn't have Linux but Windows Mobile is very hackable and has much community support from Xda Developers.
actually you can run ubuntu and android on the HD2 heres a list of the progress they made in the HD2 http://htc-linux.org/wiki/index.php?title=Leo/Status you could search on youtube if you wanna see more, it's pretty nice, you can even make calls on ubuntu, but the sound is a work in progress.