Victoria Miniatures now has their 10-man Rough Rider conversion kits available in resin.
From the announcement:
Hi, I’ve just added the latest resin product to the shop. This is a small production run testing the suitability of the resin as a material for the long lances. It will flex but not snap easily and any adjustments can be made easily by immersing the arms or legs in hot water. Hopefully a better solution to bendy spears than the soft metal version.