Another option that may appeal to you, depending on your handlebars and ****ers (or mirror) is something like the Bontrager Beacon lights. They use AAA and come in either drop bar or flat bar variants, but IIRC, the run time is inflated. I think mechBgon has/had these and also believe that he mentioned that there is a little rubber thingy that will need to be replaced from time to time.

You could run the bar end lights on your group rides and get like a Radbot 1k for the seat post. The Radbot could be active while out in traffic and then passive (does double duty as a reflector) for group rides/MUP.