OK. This post is just to 'close the loop' on the greasable bushings for those of who wish to do this in future. Just as a note, I got mine from Summitracing.com because I had a store credit there, but the prices were just about the same as Jegs.
Bushings for Rear Z0K swaybar (1 1/16"):As others have said the Energy Suspension
9.5162R (Red) or
9.5162G (Black) are the correct-sized greasable bushings for the rear Z0K bar. These also have radial and crossed grooves inside to (presumably) retain the grease around the bar.
Bushings for Front 1 5/16" swaybar:This was where it got a little more difficult. I first went for the 34mm Mustang bushings per the posts in this thread - Energy Suspension 4.5193R. But despite the picture showing these with Zerk brackets, they are actually just the plastic bushings ONLY. They do however have the grease-retaining grooves inside and looked like they might fit in the OEM brackets (though I did NOT verify that). They certainly fit around the front sway bar perfectly, and are actually marked as 1 5/16" (not 34mm per the Ad). I called Summit up and complained about the missing brackets. They looked up the correct bushings WITH brackets and sent them out (paying for shipping both ways, having UPS do a pick-up of the wrong ones), though they did point out that the small type in the Ad stated that they were bushings-only

Note: they tried to look up the Solstice but had completely wrong sizes in their database. So I insisted on the size I wanted and they sent those ones.
The replacements are the Energy Suspension
9.5167R (Red) or
9.5167G (Black). These
do fit the front sways and
do come with the Zerk-greasable brackets. They do not, however, have the grooves inside to retain grease. This is probably because they have very thin walls - the brackets are exactly the same as the 27mm bushings above, consequently the plastic is thinner to fit around the larger bar.
UPDATE: Per goat's post below, a warning for these latter 9.5167 busings & brackets:
"I have a set of the fronts you listed, I tried them and took them off. the thinner bushing creates just a little pre-load on the front bar, this is not something you want unless you are an expert (not me)."
Hope this helps someone...
Added by request, links to these at SummitRacing (Jegs.com is just as good I'm sure)... These are the red ones:
Fronts:
http://www.summitracing.com/parts/ENS-9-5167R/ Rears (Z0K):
http://www.summitracing.com/parts/ENS-9-5162R/