There are a few ROMs with pinch zoom Google Maps, including Evil Eris 2.0 and KaosLegendary. I have tried moving all of the maps-related files and frameworks to our phone (rooted) to see if I can make a basic Eris 2.1 ROM have pinch zoom maps, but with 0 success so far.
Once the actual OTA comes out, Verizon says it will have pinch zoom Maps. So, at that point, we will be able to have Pinch Zoom in Google Maps. Very soon.