There is a gravel you can have put down that over time will pack down in to a blacktop-ish surface. I couldn't tell you what it's called though.
I'm no expert but I was told (when I added gravel to the previous owner's gravel drive) that the original gravel was too big/course to really pack and the replacement stuff I got (finer) seems to become packed very well (especialy where the tires regularly run and where my wife's sport ute sits).