I don't about any virtual kits... but if you mean from FIRSTCADLibrary.com, there were two pneumatic cylinder downloads on the site.
Well, apparently FIRSTCADLibrary.com is down due to the lack of bandwith, but you're in luck. I found two pneumatic cylinders on my computer. They are the 3/4-inch bore and 2-inch bore downloads. I uploaded them to a Geocities account. Get them here:
3/4-inch bore
2-inch bore
NOTE: After extracting the .ZIP files, the Inventor files are in .IGS format