I've been working for a couple of weeks on a RepRap Arduino Mega shield. I've got a mix of early generation 2 electronics, a few home-made single sided generation 3 stepper boards, and old arduino with a screw-terminal shield and a brand-new arduino mega.I designed myself a version of an arduino mega shield to connect the gen3 stepper boards using the 10-pin IDC cables, and it might be useful for anyone transitioning between generations of electronics. Features:You can treat this as more of a prototyping board, and solder as many headers/pins as you need: I bought a dozen 50-pin headers, so I filled mine up. I'm only expecting to use one or two of the analog inputs as temperature sensors for now. NOTE that the +5v/Gnd/Signal headers for the digital and analog pins are directly connected to the internal arduino 5V supply. DO NOT run anything major off these headers. I was only planning to add simple data switches (digital input from high/low), simple thermistor circuits (Analog input) and potentially a small servo (9g micro servo) off these I/O pins - so I didn't pay much attention to them. If you are running any further circuits, use a separate power supply! (all RepRap boards have separate 12v PSU headers anyway). My build went well. I 'tinned' the copper pads (using some plumbing flux and a tiny bit of solder), which made the soldering a bit easier. Using a tip (from ladyada?) I converted some standard header pins to some through-pins by pushing them through using the flat on a pair of pliers, three or 4 at a time.Once I'd lengthened the pins, I could put them through from the top of the board into the arduino and check the alignment. I left the pins partially pushed in to maintain the position, and soldered a single pin from each row. This held them in place when I removed the mega and soldered the rest.Top Tip : apply the silkscreen layer before you solder the board up. I didn't and had to write all my pin numbers on with a sharpie. Some pictures of my build in progress: http://renoirsrants.blogspot.com/2010/06/renoirs-mega-shield-built.htmlIf you're looking for the arduino mega shield, pins only, I've got some eagle files here: http://sites.google.com/site/renoirsrants/reprap/arduinomegashield?pli=1EDIT: Updated with thicker traces and ground plane, and 0.3mm centre drills. Should be easier to home-etch.