Hello and welcome Dani-
You are correct in your belief that the Cig2o is KR808D-1 model, abbreviated 808 typically and is in reference to the threading of the connector. If you're looking to stay in that size range for a PV there are quite a few options out there. There are some upgraded versions like the Volt and Maxx Fusion that have a slightly longer battery life, or you could also opt for the standard 808's as well. These are going to have a better battery life as well as give you more options for colors, switches, LED's compared to the shorty batts that came with the Cig2o.
If you're looking to go a little larger the Joye eGo is one of the most popular PV's, its a 510 model and 510 is becoming the mainstream size for a accessories. In between the eGo and the 808 lies the Joye 510 models, these are more along the size of a Sharpie.
If you really wanna jump feet first into the
vaping scene you can go with some of the mods out there, there's a ridiculous amount of them and they vary in size/shape, have bottom feeders, variable voltage and a plethora of other features.
Or you can just hang out with your 808, most of the guys and gals here still have one lying around for emergencies, or for trips out where they might not be able to discretely vape/carry a larger PV. Feel free to look around, check out the Forum Suppliers for reputable dealers, and once you get your 5 post newbie limit you can start posting in other areas of the forum, I know PA has some active vapers in the location forums that like to set up meet n'vapes.
As always, if you have any questions, feel free to ask those too.