Yes, Kelly Chambers is bi, and possibly Subject Zero and Samara's daughter
subject zero says that she has been with girls before and sex does not mather for asari
If you use a mod on the PC version you can even make Grunt do it with Legion
The last option doesn't exactly fit the definition of lesbian ^^.
^ I was just giving an example. And it goes way farther. Just check this out
^^ And if you follow the links on the right side of the page you'll run into even crazier stuff. I think I saw a video with a FemShep wearing Grunt's armor