I have yet to spot R5-H6, though I'm guessing he's on Tatooine from all the grime on him. As far as astromechs in Clones I've seen this R5, and an R4 unit in the Visual Dictionary, the Astromech customs that I've already made only in behins the scenes stuff. In the movie itself I've seen R2-A6 in the opening scene (who a lot of people say is R3-T7 but that is far from the case), a red/white R2, a green/white R4, and of course, R5-D4 on Tatooine, and yes, I have seen R3-T7!!! Where is he you ask? Well, when Obi and Ani drag the now-armless Zam Wessel from the Outlander Club, look in the background of the first wide shot. There's a crowd of people walking by in the background, R3-T7 is on the left hand side of the screen, about 2/5th down from the top of the screen, rolling by some cargo boxes. No, he's not zapped by lighting like his figure, however we never see lighting come from Jar Jar's staff, the Geonosian staff, the Royal Guard's staff, Dexter Jettster's cleaver etc. Hasbro was just getting wacky with the energy effects :)
UPDATED - I finally got a screengrab of the shot with R3-T7. It's probably too small for you to see here, but now you'll know where to look:
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