The only practical difference between a LQMDE and LQCDE is the kind of interface - the former is PS/2 only, the latter is PS/2 + USB combo. Older LQMDEs may still come in beige with two-color keycaps though (and with thicker keycaps if older still), which I personally prefer. Consider yourself lucky if you stumble across a HQMDE or its more common DIN jack version, the HEMDE.
For force displacement diagrams of clears, best find a 2006 Cherry keyboard catalog. They have ones for blacks, blues and clears. The missing one for browns can be obtained from the MX switch datasheet.
As far as clears go, I consider them a "good" switch. Imagine a scissor-switch keyboard with some additional travel with linear characteristic tacked on (or a black Cherry switch that grew a tactile point). Tactility is not as sharp as on a board with blues, and they are heavier as well (more in line with a Model M), but they are tactile switches barely any louder than blacks and near impossible to bottom out as well. I think they strike a good compromise between typing feel and noise emission for noise-sensitive environments (I used to have such a board in the lab), especially if you have a heavier touch.
As for ripster's theory, well, clears and browns do have their tactile point quite high up, so it's quite possible Alps switches serves as inspiration, but the feel of clears really is not very Alps-ish.
Regarding clears vs. browns, the browns have a sharper but lighter tactile bump and are lower-force switches in general (more in line with blues in that regard). Here in Germany, they aren't obtained very easily on the used market (which is not to say we'd be drowning in boards with clears, but at least those have been sold in regular G80-3000s; yours truly lucked out with badly described boards twice).
