I have to say that its pretty disappointing Milwaukee did not see a way to retrofit the latest M18 battery design to V18 tools being that other manufacturers are doing it now. But that what sells more tools I guess. I looked on Amazon didn't see any knockoff batteries either. Buying $100 old technology batteries hard to justify. New OEM batteries for my NiMH Makita are not much cheaper but there are knockoffs to be had on them.
I you do go new (and with Milwaukee again) they have also just replaced their standard brushed drills and impact drivers with brushless technology so its not just the FUEL models anymore. A less expensive option.
I recently added a brushed M18 hammer drill to my tools because they were moving them out and the price was $60 off list. It came with the compact batteries but I didn't mind because I already had some 4.0XC and wanted a couple of lighter batteries anyhow. But getting the largest XC's is the way to go if you don't have any batteries. Run time is amazing.
Best M18 deal IMO is the Fuel 2797-22 combo and its still advertised with a free 4.0 xc battery or recip saw at the
HD online