I have been ruffled by a rumour that Save The Queen can be synthesised as a weapon for Steiner. I'm pretty sure it can't so could somebody shaed some light on this or give me closure. Thanks.

As an item you can gain? Yes, most definitely.
As an equip-able weapon for any playable character? Sadly no.

To get Save the Queen you need to first open up Hades's Synthesis Shop by defeating him in Memoria in disc 4. The items required to synth Save the Queen are a pair of Silver Gloves and a Javelin, and costs 50 000 gil to synth.

So, why even bother synthing them when they're useless? Well, about the only thing you can do with it is to have Amarant throw it at an enemy in battle for massive damage (I think it also has a fire element too, but I'm not sure), making it still a 'weapon' of sorts. But it's still not worth the item investment and gil sink to do so.

And finally, despite the rumours to the contrary, having Save the Queen in your inventory when you defeat the final boss does not, repeat NOT give you an alternate ending or anything special. So yeah, it's a pretty useless item to have.

Ok, thanks. I know all the Necron fluff though, like using Phoenix Down has a 45% chance of killing him.

I believe you could also just switch Beatrix weapons when you have her in your party, so right there you get a free one.

I don't think that was possible if I recall it correctly, 'cause Save the Queen was unswitcheable?