People hiring care about GPA? Since when? Sure, for getting into grad school, but not a job, least wise, not around these parts.
As for a small firm, they will hire you for your EE work and don't expect more. Your job is to have billable hours and you doing something other than your background is less likely to be billable. Not to say you won't have an opportunity to cross-pollinate, but your employer wants to profit off of your work. There is no profit in training.
On a side note, if I need EE work, I go to an EE firm, not an ID firm with EE. I want depth, not breadth.
Yes I am being a Debby downer, sorry. The path you seek is out there, but it is not a common path and you have to sell what's in it for your employer, not what's in it for you.
On a side note, I'll be interviewing an ID graduate who has been doing hard-core engineering for the last 4 years. They probably took the job because they needed the job. Maybe it will work out, I do need someone with front-end experience instead of back-end.