To get under the 10k lb goal, I'd suggest that the Komatsu D20/21 are nice machines. Grey market machines, especially the older units, will not have proper ROPS/FOPS which can be a concern. Maybe less of a concern if tinkering on the ranch, but out doing paying jobs without proper safety equipment can be an issue. Some parts are getting difficult on the older grey Komatsu dozers. Many have the wide mud tracks, which aren't the best for most applications. Some are clutch, some are power-shift. That being said, a USA spec D21 with joystick controls is a sweet little machine. I think it would have some advantages over a big tracked skid steer, but be a little less versatile also. I've had D20/21/31 and a D3. The D31 and D3 are really nice machines. I think I can nearly keep up with a D20/21 with a big tracked skid-steer in many applications, so I am not sure it would pay to go with a dozer smaller than a D3 unless you can afford to have that specialized machine hanging around for those perfect jobs.
My son runs dirt moving equipment for a living and they have a JD450 dozer and the largest JD skid-steer plus an excavator. On smaller jobs, the dozer stays home. Bigger jobs and cutting in driveways and such, they often bring the dozer. If they were forced to sell one or the other, they would likely keep the skid-steer.
