I was looking for a good PC9 at a reasonable price for years. I already have two P89 automatics that take 15 rd mags. The PC 9 takes the same mag.
I would really like to find a .45 ACP Camp Carbine but they are ridiculously rare since November 2008. They use a standard M1911 mag and I can't think of a better carbine/pistol combo. My Ruger combo is fine but it's not .45 ACP.
The KelTec sub 2000 in 40 cal using Glock23 mags makes a very nice combination of carbine and pistol using the same mags and ammo. The bonus is that the KelTec folds to sixteen inches with mag in it, so you can carry it around in a book bag! They are fast, accurate, and reliable, and very easy to clean and feed. I range mine with Tula ammo and keep Hornady HPs in the defense mode.