So I got my geared stepper in and it worked ok my MDF extruder, until the MDF started to split where I had some screws going in through the thickness of the MDF instead of through the face of it. I went to my local hackerspace and printed out a brutstruder. The print took about 4.5 hours on the slow Darwin in the space. The makerbot was being calibrated at the time for a mendel print (a bunch of these were being printed and settings tweaked http://www.thingiverse.com/thing:4730), so I had to use the slower machine in the space. The extruder works well now and I have to adjust my settings to get it working.
My plan for a heated build platform is to use an electric skillet sitting on my Y stage. The first tests with the new extruder failed because the filament did not stick to the painters tape I had on the platform. The heated skillet should help with adhesion.
I have also made up a new 4 axis stepper controller that has further reduced my electronics footprint. You can see it and read the build instructions at http://www.johnyang.com/p4ac. I had a batch made up, so if you're interested in one, drop me a note at lj.johnyang*AT*gmail*DOT*com and we can work things out. I'm still testing things out for the next few days/week to make sure there aren't any problems with the design.
The next thing I have to do is to calibrate my machine and get it printing. It is very close now. I'll be trying to print a cathederal for my kids as a holiday present. After that the next thing I have lined up I want to print is a mendel (most likely the imperial prusa mendel variant) and a replacement shell for the key fob for my car. it is cracked and I have not had the remote for some months because of it. I've had to actually use my key to open the car door, the horror!
Anyhow, I hope to be fully printing soon!