10k seems realistic if you're not needing much body work, and are okay with a Macco paint job. I'm probably 12k into mine and haven't touched body or paint, but I'm also doing a lot of stuff above and beyond just getting it back on the road.
That said, if your current plans account for 10k, figure by the time you're done you'll spend 20
. Too easy to add stuff as you go. "Man while the body is off I should really get a rear-fuel tank," or "well if I'm doing the brakes anyways I'll just swap it to discs."
Scope creep!