Perhaps a slight detour but I made a DIY chain oiler using an old pump soap dispenser tucked behind the rear foot rest thing. I modified the nozzle to a knob with a tube down to a little brass reservoir that drips oil to the chain.
I can just reach the knob and its easy to give it a short poke when I remember and the whole thing didn't cost me much.
The one thing I've learnt is not to over oil the chain because, I guess, the aerodynamics at the back seems to suck any spare oil off the chain and to hoze the rear wheel and rear disc. Symptoms include nicely oiled chain/sprocket, very crappy rear wheel and crap foot brake.