No big hacks, but I've brought a couple of those Saeco superautomatics back from the dead. One of them had a crazy power fault that caused the dosing solenoid to emit a very loud and scary buzz as soon as I gave it power. It was so jarring that the first time I heard it, I thought I was somehow electrocuting myself. Traced it down to a bad triac on the controller board. 58 cents from Arrow.
I've always liked these, but if I were to hack one up, I'd probably want to see if I can achieve higher pressures. It has a really narrow regime of operation, and it doesn't quite achieve a high enough pressure to operate with true espresso fine grind. You have to set it to a slightly coarser grind, and the result is that it makes a fairly weak shot. But it does so with great consistency.
Definitely don't buy the newer Saecos with the BMW design bullshit. They are choc full o' nutty sensors and control circuits that make me very angry. (Too many faulty sensors is a BMW specialty.)