Are there any good horse-drawn wagon kits on the market?

You could try looking for Historex horses. If memory serves, they come in bare--no saddle or tack, but in several poses (walking, trottings, etc. Probably worth it to browse the Imry-Reisely and H&R Products stuff. Will guess that's slim pickings, though. There is/was a German Supply Wagon kit by ESCI or Italeri which had two horses in drawbar harness. Which was much in my head when I was considering a US horse-drawn artillery dio, and that project ground to a halt for not finding a couple-three of the supply wagon kits, and for not finding a source of info for the teamster's saddle the US used. Such is life.

Ypu can get a complete set in 1/72

 

http://www.ebay.com/itm/Wagon-Train-set-by-Imex-/141849098413?hash=item2106dd78ad:g:C6cAAOSwPc9W1El0

The Borax 20 Mule Team kit has been rereleased by another company. Available for about $20.00   http://dvnha.org/opencart/index.php?route=product/product&product_id=225

Long ago they used to have a model of the 20 muel team wagons that hauled borax out of the desert.  If I remember right, they usually hauled a couple wagons per team.

 

The lits were re-iaaued at one time and sent to customers who sent in boxtops of their product for a couple dollars plus postage.  I had a few back then and I might still have one in the garage. 

Being a 20 muel team , the kit might extend beyond your limit of 12 inches.

There are currently several horse drawn vehicle kits available on the market. They are military in subject but can easily be made and converted as it is what I do. They are very often on Ebay or hobby supply outlets, or check MegaHobby website. Also the old Borax 20 mule hitch model, 1:48 scale, which is often on Ebay. The Budweiser Clydesdale hitch model can some times be found, some times good for parts or for the horses.  Plus there are some wooden horse drawn kits available also. There are kits out there in the horse drawn vehicle subject just have to look around and search.

Imex makes a series of 1/72 wagons that though are a little under detailed with some work would look pretty good such as these below. Although 1/72 looks small they look great in mass.

 

ModelExpo makes a small series of horse-drawn vehicles, including a stagecoach, a Conestoga wagon, a buckboard, a chuck wagon, a doctor's buggy, and a really spectacular fire engine. They're on a large scale, and they're not cheap, but they can be turned into beautiful models. Go to www.modelexpo-online.com and look for vehicles.

Unfortunately ModelExpo doesn't offer any people or horses to go with the vehicles - and to my eye, at least, a stagecoach just isn't a stagecoach without horses.

Back in the early fifties, Revell made a series of very fine Western wagons: a stagecoach, a covered wagon, a ranch wagon, a chuck wagon, and a medicine wagon. They were quite small (1/40 scale) and they came with beautifully sculpted people, horses, mules, oxen, and various other animals as appropriate. There was also a group of horse-drawn fire engines, and some European types: an English state coast (with recognizable miniatures of Queen Elizabeth and Prince Philip), a Roman chariot, a gentleman's carriage, and an English stagecoach, complete with driver, hornist, and passengers who looked like they stepped out of a Dickens novel.

The kits didn't sell well, and Revell took them off the market by 1960. They did reappear under several other labels, Adams, UPC, and Lifelike. I really like those old kits, and I've managed to collect most (not all) of them in MPC and Lifelike boxes. (Original Revell ones tend to sell for astronomical prices.) They turn up on vendor tables at IPMS conventions, and on E-Bay and www.oldmodelkits.com .

Good luck.

Here are two very good ones but the price will set you back some. Here's a chuck wagon and stagecoach from Andrea miniatures.

 

Joe

 

http://www.andreadepotusa.com/en/1/andrea-miniatures/104/the-golden-west/920/s4-s11-chuck-wagon-1880s.html?redirect=true

 

http://www.michtoy.com/item-AND-S4-S06-Stagecoach.html

I'm afraid the heyday for this type of model was about 50 years ago. "Craft Master" made a line of wooden models; "Wagons of the Old West" that you might find on eBay. "Wagon Master" was another line. No idea of scale, but I think they are larger than your desired size. You're going to be paying collector's prices for these if you can find one.

I did find these guys;

http://kulpmodelhorsestore.com/products.htm

Maybe there is something there that would be suitable.

Sorry, I'm not much help, this is a bit removed from my knowledge base....good luck!