You typically don't need special drivers for keyboards. Certainly not for PS/2, and USB 'boards usually are plain ol' HID devices as well.
As for the Kinesis Maxim, try looking around for a Siemens / Fujitsu-Siemens / Fujitsu KBPC E in ol' Europe, maybe a UK layout. That may be quite a bit cheaper provided you don't mind an ISO layout (here in Germany they are €50 or thereabouts).
Be aware that both the big Kinesis and Maltron boards have F-keys that are, umm, F'd up - by which I mean they do not use the same nice mechanical switches as the other keys (usually Cherry browns) but rather some rubber domes or worse and are smaller to boot.
BTW, you can determine actuation force on your present keyboard using the "ripOmeter" method - level it and stack some coins onto the key in question (they have a precisely defined weight). I would recommend an iterative approach, i.e. start with the heaviest coins until it goes down, then take away one and determine the point more precisely with the next lighter kind of coins, etc.
This is a fairly one-dimensional kind of "measurement", but does give you an idea (rubber domes usually are kinda similar anyway, while with mechanical switches the force displacement graphs and corresponding feel can vary a good bit). For a FSC KBPC PX, a conventional-layout relative of the KBPC E, I determined a peak force of about 50 g recently - subjectively this is Cherry blues ballpark, or medium to low force. Like the feel, hate the lettering contrast.