How to shorten glass-fronted wardrobe doors

I need to shorten the glass-fronted sliding doors on my wardrobe, as the whole thing is too tall for the bedroom in the new house. The glass is about 3mm thick and is bonded to approx. 30mm thick wood. The three doors are about 2.3m tall and 1m wide. The doors need to be reduced in height by about 100mm.
My idea was to cut through the wood from the back with a circular saw to just shy of the glass, then lay the doors wood-side down on a workbench with the length to be removed overhanging. Next I was planning to score the glass on the upper face with a glass cutter and break it. Job done!
What are my chances of success? Is there a better way of doing this, e.g. cutting the glass with a tile saw and diamond wheel?
I will go for the method which has the best chance of success, even if I need to buy expensive new tools. Any feedback and tips very much appreciated!

I would say bring it to a glass shop, might be cheaper than replacing the mirror after it breaks.

There are some things I dont do, and that would be one of them.

I would have been happy to get it done professionally, but no one wants to touch the job, which I suppose says it all about the chances of success I suppose!
However, up 'til now no-one has given me a good explanation of why it is so difficult. At what stage of the operation is it likely to go wrong, and why?

Well the bigest problem is the glass breaking and the you will have to scrap the glass off of the door.

But if you still want to do it, there is a way, but difficult. (An I will not say how)

But if you do it the way you said make sure you use painters tape on the point you are going to cut and below.
This will help the gleass from breaking, but no guarantee.

Glass or mirror?

Tempered or annealed?

It's not a mirror, but is painted on the reverse side, the side mwich is glued to the wood. The front side has a very fine matt finish. No idea whether the glass is tempered or annealed.

To MyToyotaSucks:
I do still want to go ahead, because the wardrobe is useless to me at the moment and I cannot get anything approaching the cost of replacement by selling it. I am prepared to risk the glass being ruined, but am looking for the way (easy, difficult, cheap or expensive) with the best chances of success.
You say you know a way, but won't say what it is. Why is that? Just curious, because if the technique is dangerous or illegal I wouldn't be interested in following it anyway.
Thanks for your replies so far!

I dont suggest illeagal.

The way that is hard, would be as you suggest to cut the wood really close to the glass, while the galss is covered by painters tape (painters tape comes off easy, if left on less that 10 hours).

and once the wood is cut, you would take a strip of tape off where your going to cut the glass and then score the glass with a glass cutter (around $10)

(ok this is the hardest part cause it takes training) then take some lighter fluid and pour (just enough to make the fluid about 1/2" wide) it on the cut line and lite it, and then snap the glass.

The fluid will burn itself off, and the heat almost always keeps the glass from chipping or breaking. But takes training to do it right, thats why i dont really tell people to do it.

And the other way with fluid , is to cut the wood with the painters tape on the glass, remove very little tape from the cut point, score the glass and then use the ball end of the cutter to tap the score point and break.

When you score the glass either way, do not press too hard cause that can break the glass or crack it.

Ok i think thats everything, when doing it myself i dont have to think of the steps, cause i did it for years.

You might even look on you tube and there might be a vid on this.

Good luck.

To MyToyotaSucks; thanks for taking the time to describe your methods in so much detail. I have looked on the web, including Youtube, and found lots of info on scoring and breaking glass, but wasn't at all confident until now that it's appropriate in my case. So now I know that it is not definitely doomed to failure I will go ahead and hope for the best. I'll take some time to practice the technique on some unimportant pieces of glass beforehand though.
Just a couple of final questions if I may.
When you burn the lighter fuel, does the tape either side of the score line get burned too, and if so does this matter?
I have seen some people cutting glass during my searches on the web who insist that the glass has to be lubricated with a light oil beforehand in order to make a really clean cut. What's your opinion on this?
Thanks again for your help.
Steve

Ok, first you dont want to burn the tape, just take alittle more off if you think it will burn.

And as for a lubricant, ive never used any. Not saying its bad, but new tecniques come all the time, I use my tried and tested methods.

but when you do make the score line, make sure you use some type of guide, i think i forgot to say that.