I would rather not have to build my own, but so far I havn't been able to find one that fits my needs. The best I have found so far is one that lets you physically move it in 3 DOF, while the other 3 DOF remain braked.
I don't think anything exists that fits all of your requirements and vague specs.
For example, what do you mean by "with ease", what is your repeatability requirements (I'm thinking of reading encoder counts as you move the arm), end of arm mass exactly (not "a few pounds"), work volume exactly (not "fairly large")? There's lots of work to be done here. The issue with
6-axis arms is the gravity thing: individual axes must be braked so as to not allow the arm to drop due to it's own weight. One can move an arm via teach pendant or maybe even manually, but it's just not as simple as grabbing the tool flange and moving the links as if it had zero mass. Otherwise we would all be using FARO-type portable CMM arms to do robot path work. And what do you mean when you say "exact path": axis-by-axis motion or fully coordinated motion with path planning?
And the biggest question: are you a hobbyist, academic, or do you really have some serious money to spend for this device? Yep, lots of work to be done. Or maybe re-think your requirements.
You may consider developing your robot path through CAD data. One company I have seen for this type of solution:
Or ou may consider this device:
It's a rig that allows a user to record 6DOF points in space by manually moving a hand-held device. The points can then be converted to robot 6DOF robot locations in most robot's native language format.