Yes, but don't forget the direct drive extruder motor and the new MK6+ hot end and black nozzles. That's the trick part. Also, The big reason for going with gen 4 is the motherboard with SD card slot and the interface so you can run the bot standalone.
All that stuff can be done on RAMPS, but it's not stock, you gotta wire it and make it, hack some firmware-blah, blah ,blah. The fact that I can now use the exact same profile across my bots with Rep-G 25 has a big part in staying compatible with MBI. I think others are taking my cues and following. The mechanics of the bot can be whatever you want. Size is only limited by your motors and drivers. I've even done the whole servo feedback test too and shown that works if you want to spend the money-and even that's not horribly expensive to use Gecko drivers.
Also to be in the works-a RAMPS like board instead of the $85 motherboard and $90 extruder board that is electrically and firmware compatible. No reason why it can't be done and further-throw in the Sparkfun Quad stepper driver functionality (basically 4 Pololus on the board as well). Zach has had a single board design up on the MBI repository for a while.
Again, the key is to follow MBI at least in some aspects such as firmware and electrically compatible so their R&D for upgrades is compatible.
The logical next step is support material printing-and that's just looking like software and firmware holding that back. There are a million designs for dual extruder heads and the motherbard hardware is ready for another stepper. The extruder controller has the extra mosfet and thermistor ports if using dual heaters. As long as what we build keeps those things in mind-we are in a very good position.
