I carry a .32 acp Beretta Tomcat, and a CZ70 in 7.65 Browning/ 32 acp (i list it as 7.65 because it diesn't like most 32s, but eats import fiocch like candy.
I've also been known to OC my Nagant revolver once or twice...
I usually carry either a Glock 20sf, 29sf or Delta Elite (not often on that one) so I guess I qualify as carrying an odd caliber. But, I think 10mm has a bit of a following and would not classify it as too odd. Then again, they don't carry 10mm ammo at Meijer's, so maybe it is odd after all.
I regularly carry my FH FiveSeven in 5.7 x 28. I am especially prone to carry it on trips, as I can pair it with my PS90 and only travel with one type of ammunition.