On the odd chance you have not come from one of the two following sites, if you have an interest in gaming or military miniatures you really need to check out:
I also have a Napoleonic siege gun and limber, and for now I will be using this limber to match up with the sling cart. The gun and limber is scratchbuilt from Evergreen plastics, a wooden dowell and some brass wire. The horses were done in green stuff using a ground down Essex horse as a dolly. I had a few of these cast for my own use and they also feature on my Union pontoon wagons.
...and my old friend the Redoubt 28mm VMI cadet is shown for scale.
Check out the ACW, Extras, Regiment packs.