Sadly, ramming isn't something that can be implemented as long as hisec exists.
Explanation:
Let's say that it is possible for ships to be damaged by collision. The problem is that this can happen by accident.
This either means that you can get concorded by bumping someone coming out of jita by complete accident, or that you can destroy someone's ship without concord interference because it considers ramming accidental. Either way, you've completely fucked up something.
The only possible option is to have some toggle-able option to control whether you want to bump someone or ram them, complete with concord warning (like activating a smartbomb in hisec). OFC, this makes no fucking sense IC, but oh well.
It would also make the plated bump-stabber the ultimate weapon of suigankage.
There was a forum thread on Features and Ideas at some point, which I am to lazy to find right now, but which outlined a module that you could fit to a ship:
The module would have relatively light fittings requirements and once activated would serve as a combination of targeted MWD, accelerating you towards a target it was activated on - and extremely short-ranged AOE weapon that would do damage proportional to your ship's mass once you reached a certain (very low) range from the target.
To counterbalance this, it would also have the effect of slicing off a good portion of the fitted ship's hit points and drastically reducing your CPU and PG output, making fitting a significant tank through modules impossible.
A good number of posts in that thread were dedicated to arguing whether it should be allowed in highsec, with most people arguing it should not be. It ended up being a moot point in the end, as CCP stepped in and gave a software/networking explanation of why it was unlikely - very vaguely, I think it was that to make the module effective it would have to place an overwhelming number of calls to the server to determine if it was in detonation range, and they didn't want to do that to the server.