Thanks for a very interesting link, Fortyfied. There is some really unusual and interesting stuff going on there.
1badmagnum- what do you want this carbine for? If you want a light, concealable carbine, and can do with a pistol cartridge, how about the new folding Kel-tec Sub2000? The new ones (unlike the previous model, which had some major quality control problems) are supposed to be good guns. That is, if you can beleive the magazine reviews, anyway. The 2 new ones I've seen looked to be good, and it gives you a carbine that can fit into a backpack or suitcase. This means you can transport it pretty much anywhere without scareing the straights or challenging the whackos. Of course, a handgun is better, but what about out of state where you can't legally carry?
You could spend most of your budget on ammo.
Another good carbine is the old M-1. Numrichs is selling .22 Johnson conversion barrels, factory .30 carbine mags still work (or at least as good as they did in .30 carbine), and RCBS has the dies. You get a light, handy rifle that puts out a 40 gr. .223 bullet at over 2,100 fps. It's a near perfect survival/woods rifle then, and with a bit of thought in bullet selection it makes a handy self-defense rifle.
There's also nothing wrong with the original .30 carbine, although it has to have a bottom-rung "Gee-Whiz" factor.
What's important to you?