Turning a tank into a shallow

I have a 29g tank that has no use to me. it was drilled on the bottom pane using a dremel and lets just say it just didn't turn out the best. I have since retired that tank and moved on to a new 29G. So in my never ending quests to modify/change/destroy everything possible I have an idea I need to make come to life. 
I plan on chopping the tank, but my question lies in exactly the best way of doing it. I know that totally stripping the panes down and reassembling after i have my desired cuts. But, what if i were set my straight edge as my guide, run my glass cutter along each panel, and use piano wire to cut the silicone down to the target area, and then snap the pane. 
also is there any suggestions on sanding/polishing the edges? id like to make this a rimless but ill tackle one obstacle at a time.
feel free to brainstorm here. I'm not out anything by trying. id like to hear what other think. maybe we can actually get this to work!

 

That was the biggest problem I was running into. I knew it really couldn't be that easy. So my options are completely tear it down and reseal it? With it being shallow do I have to worry about a top brace even at the 30" span?

 

Well I guess ill find out!