G'day and a question about switches

[Jaxon]

G'day all
Thought I should ask after some fruitless searching.
Currently I am using a Rosewill RK9000RE but I am looking for a change.
I was wondering if there is a key switch that activates at the top of the stroke instead of in the middle like most common cherry switches.
The circuit would be closed when not used, but open when the key is pressed even near the top.

[brentaarnold]

I don't know about the actuation circuits, but the Topre's actuate towards the top of the key, I believe.

[Lpwl]

Welcome to GeekHack ~

I'm thinking about keyboards with optical switches like these ones made by a taiwan company named Bloody.

It seems that these (infrared) switches only needs 1.5mm to actuate.

[Moistgun]

All I know is that Gateron switches are supposed to have a higher actuation point, but its not that noticeable to most. 
Most likely not the kind of actuation point you are looking for. 

Those infrared switches look interesting!

[rowdy]

Welcome to Geekhack!

Cherry switches, and probably most Cherry-compatible switches, have a 4mm stroke and actuate after 2mm.  You can use O-rings to reduce the total distance to bottom out (and also reduce the bottom out sound), but they do still need that initial 2mm travel to actuate.

Topre switches are capacitive, and actuate when you bottom out.

Er, Alps are similar to Cherry, AFAIK, although with only one Alps keyboard (and that in an old typewriter of questionable workability) I have no way of testing it.

Buckling springs actuate at the bottom of the stroke too.

Cherry MY might have less travel distance, but the overwhelming majority of users despite that particular switch.

Something with scissor switches, like the Apple aluminium keyboard, has a very low actuation distance, but you might not want to go that route.  AFAIK there are a few other PC-compatible keyboards with scissor switches (although it is quite possible to use an Apple keyboard under Windows, as I did for a while).