YES
I'm happy to announce that the effort made by @rakshithbk [GitHub - rakshithbk/GRBL-H-Bridge: A simple arduino CNC plotter which uses GRLB with H-bridge for driving Stepper motors. Uses DC motor for pen control mechanism.] to port GRBL onto H-bridge devices is remade by me ^^.
Some explanations and instructions I've uploaded here.
The goal was to build a complete system that emulates real machines out of CD-ROMs and possibly cheapest parts. I will not try to explain how to build it here since many howtos can be found on the internet.
Parts I used: two h-bridges (despite high voltage drop - only ~3V out of 5 goes to steppers), cheap USB charger, two steppers from CD/DVD-ROM, laser.
How to modify further versions is explained on my page, so go there and read if You want. There are also modified files ready-to-upload.
What was sacrificed:
- there is no longer Z-axis. I believe it MIGHT be possible sacrificing other pins eg. spindle direction or analog.
- no Z-limit. Also, it might be worth trying to back it up when Z-axis, but not in this project.
- motor enabled. Stepper drives need to be turned on always.
All the rest of functionality should be intact, but even limits weren't tested yet.
What can be done:
- I'm going to implement my (not published yet) microstepper library for H-Bridges. Yes, it is possible and I made enough tests to say "it works!". So maybe in version 1.1 ;). It uses PWM so it may or may not work with GRBL (but I believe it will).
- restore motors enable/disable and Z-probe functionality by sacrificing analog pins.
- sacrifice more analog pins to restore Z-axis. Microstepping for three steppers is impossible, so only full steps are an option.
I would be very happy if You can test this modification and comment on what do you like about it 
Go and test it, by downloading from here!
Best Regards!