Keep applying to any of the OEM's- but be ready to relocate to SE Michigan- everyone, outside of Honda, have tech centers here. And I do mean everyone..
When they ask for experience with tuning software, remind them that 1) it's generally not available outside of a calibration organization (and I mean a real one- like Bosch or any of the OEM's), and 2) they are pretty easy to learn. In +20 years, I've been through 3 totally different systems, and still have not had to use ETAS (thankfully...). They are not that hard- especially if you've done ANY calibration- it's a matter of setting up the emulator, knowing how to change calibrations, record, and reflash. The far harder part is to know what to change, and that's more about reading code.
Code wise- lots of people like Simulink code, although I can't stand it. Know your C code. Understand the basics of engine control (it's a big air pump that you need to know how much fuel to inject and when to spark). If you can read a code book, and understand the basics, you can read the advanced code we all use and figure it out.
Beyond that, it's kinda what you want to specialize in. There's a ton to calibration- starting, stopping, shifting, transinents, emissions, driving, etc- most need a team of 6-8 to just to the engine part, in the car. There's also a team who do just dyno work. And a team for the trans.
I know Ford has a program for college grads where you rotate around for a few years understanding how it works and finding a nice home. I'm pretty sure GM has a similar system. Chrysler- not so much- too short staffed- but you'll have to jump in with both feet (from what I undertand).
Then there's uniquness to Hybrids- a different animal.
Lots and lots of opporunities out there. Be flexible, be clear that you can figure things out quickly.
FWIW, I started as on the college grad program at Ford, and found a home in Advanced and Research. Oh, and we use ATI more than ETAS, and I've never dealt with Melco- in other words- be flexible
Eric