I was navigating through ebay and I remembered that there are a replacement key fobs that are really cheap and would be perfect for my project!
This way I didn't need to design a new box or fit the electronics on the old remotes!
And more! I can make a copy of the ignition key and get a identical setup to the more modern versions!
Here's a photo of it:
I don't need the 3 buttons but I'll find a use for the trunk one :) panic button maybe?!?
My setup uses only one button as the alarm only uses one signal line for the open and close command. Maybe later I'll change the alarm microcontroller and make my own version... but for now this is the way :)