Stephen is a tricky one to pair, names ending in an N or S don't sound quite right in front of it and most of the names I love appear to be ending in an N :) I think a vowel ending would work best. I'd also avois names starting with an S, otherwise you'd get SS initials.
trying anyway (I'm trying not to made the combo sound bland, so maybe these seem a bit weird...):
Bronte StephenLaszlo Stephen Ezra StephenDante StephenLuca StephenKyler StephenNoah StephenOscar StephenImre StephenGabriel StephenMilo StephenJago StephenHugo StephenTaro StephenJoshua StephenJosiah StephenJesse StephenLeo Stephen
btw I'm not sure if I'm pronouncing it the same as you, are you saying: STEE-vun or STEF-fun