The whole War in the Pacific thing that ended up with me publishing "It's Getting a Bit Chile" was given impetus by me finding an actual range of 15mm figures to wargame the period.
I'm a 15mm bloke for this sort of period as it seems to give the best balance of size and detail in a game with rifled firearms, so that sorted me fine. Then I published the rules and people seemed to have an aversion to 15mm, or perhaps more of an affinity for another scale. So people said "I'd buy these rules but no one does figures in the scale I like". I then pointed out that you could use a mix of ACW/FPW and other European wars of reunification figures to cobble together some armies. A lot of this discussion took place on the Baccus 6mm forum, and then subsequently on the blog of a French wargamer who styles himself "L'Empereur bete et mechant". It seemed it was possible. L'Empereur wrote a blog about his thoughts and plans here, and then an update when he got the figures from Baccus here. The figures he chose as proxies were listed on the Baccus forum here.
But he wasn't the only one. Another, unconnected, French wargamer in 6mm, named Patrice Deffayet stole a march on him, and posted these pictures on the 19th century wargames Facebook group:
Stunning. The flags are HAND PAINTED!!! I asked if hem inded me posting the photos of his work, and he consented. The man is both a genius and really nice like that.
So, in conclusion, it is possible to use other figures in other scales, and they can look awesome.
No excuses now, chaps, go out and get a copy of "It's Getting a Bit Chile". Only £14.99 from Amazon.