single speed
 

Does anyone know where I can get my hands on a single speed conversion for the e-maxx, or how I can do it myself?

Ask Mike when they will be back in stock. The only places i know which stock gmaxx parts are as follows;

www.rc-monster.com
www.2coolrc.com
www.rcbros.com
www.gorillamaxx.com (under renovation of new products)

If you cant get it, you will have to wait until some new ones show up.