Thanks to a fellow builder, I've ordered some parts and pieces today that will make piecing together the feet a bit easier.
Jerry Chavalier shared his configuration for the center foot. Rather than using the omni-balls, which are rather noisy on any hard surface, he provided the group with a readily available caster. This one is a 2.5 inch one available from any Home Depot. I forgot the SKU but can re-post it later (or you can ask Jerry). His mod was to remove the plastic wheel in that caster and replace it with a 2.5inch rubber tire from McMaster Carr (part # 2829T15).
While shopping around McMaster Carr's site, I noticed that they sell caster axles. Since the wheel has a 3/8th inch hole, I found a 3/8th inch axle bolt (23595T14). Upon receiving the parts today, the axle is a bit too long, but I am pretty sure I can shim that up to make it snug. (I'll follow up this post with some photos)
By next week I'll tackle sawing the old axle out and removing the plastic wheel. Then get into replacing it with the rubber wheel. Jerry provided a few good pictures to demonstrate how the casters fit inside the center wheel. It looks like minimal drilling into the pre-existing plate that held the casters.
He was also kind enough to share with me the website and part number for the belts I need for the JAG NPC Footdrive. Several builders have noticed that the belt is a tad long, especially since it comes into contact with the knurled detail pieces.
In case you are in need of the shorter belts, they are available from http://www.sdp-si.com . The part number is A 6R55M065150. You will need to get into their online store before you can search for the item. I bought two, with a grand total of $27, then $12 shipping. I'd groan about the shipping costs, but with diesel fuel prices soaring, that's not a terrible fee.
So once again I have all the accessories. I just need to break down and buy the NPC motors! However, I have a few other parts I have committed too that are ready to be paid for. Another set of battery boxes, holoprojectors and another center foot are all set and ready!
Again, not much progress news but I thought I would share those part/piece sources in case others needed them.
Til next time!