Because the people who work at unicycle.com are silly 
Fair play, cheers!
With uni, as the power of your legs increases the option of shorter cranks opens up (in general, not for trials). Say on a big wheel uni for distance, starting of with short cranks will leave you with very little control but as your legs get stronger and you can control the uni better the benefits of shorter cranks opens up.
<<PERSONAL OPINION BELOW>>
I have recently dropped down from 135s to 125s on my 19". There is a noticeable loss on control under one kind of circumstance. For example when I jump onto something kinda high, if my weight is a little lower than it should be the 125s will roll out from under me more often, where as the 135s would give me a little more leverage. Other than this one circumstance I like the 125s much better for everything I do. I have raised my maximum hop height, as well as feel as I can balance better, pedal smoother, and feel more comfortable in any pedal position. As my legs get more and more used to the size I start to feel as 125s work great for all my kind of ridding.
As for spokes. I dont really mind the 36 but would prolly be happy with the strength of 32. AS long as the space between the spokes didnt open up much more. Having enough room for your foot to fit into more often would make for more falling as well as not being good for the spokes.
Iāve read that cranks that are too long or have too much Q-factor, riding skinnies is harder. (I like lots of Q-factor, especially rolling through bumpy terrain, but my skills are pretty weak)
Something I noticed once when I had 150ās on my 20, was if you were side hopping something similar to steep, narrow stairs, the pedal would more easily touch the next stair w/ the same amount of wheel movement than w/ shorter cranks. (Good/bad?)
hows the kris holm 20" trials? is it way better than the nimbus and qu ax? is it worth that much money?
its a lot stronger then the nimbus and alot more ride able then the qu-ax also it is alot lighterā¦not to mention that its one sexy unicycle!! 
in my eyeās it is deffinatley worth the extra ā¦ however dont let your brother leave it behind the car and your sister back over it!!! i mean its still ride able but it cost $20 to get the buckle out and it has a broken spoke!! lol i was so annoyed!!! anyways hopefully Kris will bring out a new model this year and i can get one of those!
Oh i bet to differ. The nimbus IS stronger then the KH and is only about 2-350 grams heavyer. in my eyes its not quite worth the extra 250$, but if i had the money i would get the KH.
how?
It doesnāt really matter which is stronger, because they are both stronger than most people need.
Wide rim makes the kh win though, and the frame 
The rim is drilled and aluminum. the max hight for a jump on a KH drilled is 6 feet.also aluminum is The frame . nimbus frame is made of steel (chromoly)
Nobody reallly breaks the kh frame unless they ride flat.
ā¦or your initials are JH and your name rhymes with hoe jodges.
Ok, besides him and a few other cases.
yes, the rim on the nimbus is aluminum too.
Aluminum frames are quite strong, arguably stronger than steel ones.
I have done 7ā drops on my drilled kh rim, itās still fineā¦
I have done bigger, and my rim is still good. I dont like it though, cause comparing it to the undrilled rim, it goes out of true way too easily, and compared to the Alex DX, it just kinda seems flimsy.
Its still good, but I find myself trueing it a lot more than I ever had to with any other rim of mine.
Anyways, for trials, I like 140s, or 137s. I ride with my seat pretty high, so the length doesnt affect my speed or how smoothly I can pedal, but if I ride my friends Qu-Ax (145mm cranks) with his seat set as low as he has it, it feels very sluggish.
Ive done trials for years with 125s, and less q-factor, and it was ok. Somewhat zippy, but not bad.
When I switch over to the Qu-Ax 145s, or Profiles, which both have a higher q-factor, I love them. My stance is a bit wider, so my balance feels a lot better, specially on natural lines and when doing anything with a skinny.
My main ride now is the KH trials with 137 cranks. I still can zip around just as well as I did with my 125s, and they have a higher q-factor, so I get the wider stance on them and I love that. For me, 137s-145s are the best for trials.
Spoke wise, I dont think id ever go down to 32. I ride kinda big, and most of the time can rollout on drops, but a lot of lines wind up with me doing a 5 foot drop (or bigger) landing to a ledge, and if I rolled on the landing, id go into a bush, or fall of a bigger drop with an awkward pedal position.
So combining a 32 spoked hub to a mag rim, I dont think that would last for me too long.
So far my favorite has been the 48h Alex DX32 rim. That thing was so stable. Wasnt the widest rim, but that wasnt ever a problem for me. Im happy riding a 36h rim right now, and that holds nicely for me too, but not quite as well as the 48. Once I get a non-drilled 36h rim, im sure it will be closer to th 48h setup I used to ride.