well....you kinda answered your own question as you dismissed any options available to you. but i'll take a stab..
though i haven't used the 24-70mm 2.8II, it looks as though it is a stellar lens. much better than the Mrk I (which i own and preferred over the 24-105 in overall performance). the Mrk I version has a useful if not true macro capability for getting close to small objects, not sure if the Mrk II duplicated this feature or improved upon it but i would be shocked if it didnt.
i never found the 70-200mm unbalanced on a tripod so long as you mount it via the supplied collar. couple it with a ballhead and it can be a pretty fluid setup for recomposing on a set of sticks. it is also a tremendous performer especially for headshots. but if you seriously aren't comfortable with it then i would suggest the 100mm 2.8L Macro. great for headshots and will cover any macro/close focusing for small product type shoots.
In my opinion Canon needs to make a F2.8 24-105 or F2.8 28-110 both with slight macro that is tack sharp, little distortion & vignetting whilst having a smoother OOF / bokeh than the 24-105 or 24-70 more like the 50 1.2. And I would pay a lot for this
thats a pretty tall order for a single lens especially over that range of zoom. zooms will always sacrifice in one area over another by design so we are kinda forced to incorporate high end primes if we want the kind of performance you are looking for.
again, i have gotten great use out of my 24-70 28L and was never impressed by my friends/colleagues shots coming from their 24-105mm 4L's. i even did a head to head comparison on a shoot with another photographer and both of us agreed the 24-105 came up short on IQ compared to the 24-70 mrkI.
i would say get the 24-70mm 2.8 mrk II. it appears to be an absolute great performing lens.