I really hope the chain doesn't fall out and hit me in the face.

Live Axle build.  The theory behind this is simple. 
Im having 4 bearings inside a tube, holding a jack shaft with various adaptors and spacers.

I have drawn over mandrel steel tubes with holding the bearings and i have an small tube holding the bearings to the outside where most of the load is. 

I chose ball bearings because they are recommended for higher rpm but the downfall of that is that they are recommend to take a radial load and not so much a trust load, which can lead to scoring of the bearing and premature wear.  I got one sealed bearing for the outside and an open bearing on the inside because i would like the keep the inside bearings greased by making a grease nipple inside tube.

Looking at the CAD model:

I have the purple flange as a spacer to bolt to the CV joint.  The bolt pattern is 4 X 100mm, for a Mazda Rx-7 or Miata, which I'm going with because the price was right on ebay.

The blue flange has the bolt pattern 6 X 5.25" for the sprocket and brakes from Hyperracing.com. 

The red flange is to bolt it to the inside of the engine mount, which is slotted to remove the chain if needed.  Also the inside slot is undersized to hold in the bearings from the axle.

McMaster Carr: $90
http://www.mcmaster.com/
Discount Steel : $20
http://www.discountsteel.com/