Good idea. With the more usual angle configuration you end up having to mount the carriage on a 45 deg chamfer of some description. With this, you get the bearings at 60 deg and a flat on top/bottom. to mount the carriage.

With the bearings being at 60 deg, they would be best run on round or hex rail rather than 90 deg angle.

Also, does this mean that you are going to have to drill and tap the bar stock to fit the bearings? No big deal for you guys, but might not suite a beginner.