I just bought a used can from stroker 2 weeks ago for the same reason. I missed out on a "professionally" shortened can a few weeks ago on ebay that ended up going for about $65. It had been shortened from 5" to about 2.5".
I cut 2" out of mine because I determined that any shorter and my fingers might hit the dash pad, but I forgot about the signal lever, so I'm gonna have to bend the lever back somehow. It almost hits my rimblow wheel at about the 8:30 position.
Anyways, I cut the 2" out myself with a 10" metal cutting circular saw blade on my miter saw. You have to plan your cuts carefully, allowing for good contact all around for welding the two pieces together. Then after laying a solid bead all around you have to grind, and then fill the low spots with primer, sand, sand, primer, trim paint etc. It took me about 4 or 5 hours of work probably all told. Maybe more, but who's counting when you do this stuff for fun, right?
It looks great, and my arms fit much better.
If you're up to it, or if you have someone do it, make sure it is welded properly. It is afterall designed to protect your chest in an accident, and cutting anything off will theoretically give you less protection, and it may not even crush at all, period. Last thing you want is it easily breaking off and the base going into your chest!
Now, after all that, I also understand that you might be able to use a b-body can, or even a tuff wheel adapter, both of which may be shorter than e-body cans. Check ebay.