I have some old 16mm films that I need to digitize (for cheap) for a documentary project. I was able to source a 16mm projector, and have tried to shoot the film as front-projected off of a portable screen. I'm facing sync issues with both cameras I tried, my Canon 5D Mark III and a Canon XH-A1. The 5D3 has scan line issues (slow, top to bottom lines crawl) that exist at all shutter speeds and framerates (24, 30, and 60). The XH-A1 exhibits a strobing phenomenon that goes lighter to darker repeatedly, every few seconds. And that camera's ClearScan feature does not go below 59 Hz, unfortunately.

I realize that these issues crop up because the film is projected at 24 frames per second (or something close to that) and my cameras can't sync up to the exact shutter speed of the projector.

Is a full-blown lab telecine scan my only option here (at upwards of $0.60/foot), or has anyone tried something else that works reasonably well?

That price sounds a bit high, you could check out a few places for quotes. You can often strike a deal.

Here's one lab that I've heard recommended:

CineLab 16mm film processing and video transfer services (http://www.cinelab.com/16mm.html)