I'm not sure how many boards you can find with Mx clears and a tenkeyless layout. But here is my limited opinion switches to the noise conscience consumer. I have only owned browns, and in my opinion the tactile feel of them is next to worthless. The small bump when depressing the key is so small that it is worthless to me in determining if the key has actuated or not. Many then would conclude that clears would be the way to go. But I have heard form many people on this forum that instead of clears being a heavier, crisper version of browns, they instead feel very "mushy". Blues are heavier and crisper then browns, but are out of the question for you most likely because of the noise that they make.
Because of all this, I think that if you want a very quiet portable keyboard that can be used at work, or say in a library, the best way to go is a linear switch, most likely reds, with an o-ring mod. The red switches are very light. They don't have a useless barely tangible bump like the browns. And with the o-ring mod would be very very quiet to type on.
Addressing the Leopold TKL, I actually have this board, and I feel it is very good for a person looking to preserve desk space at home like myself. But as for being portable, this keyboard is a Goliath compared to the mini keyboards such as the HHKB, the Poker, and the Noppoo mini.
My personal choice for a quiet portable keyboard would be the Poker based on the good looks and reviews written by geekhack members and various other keyboard enthusiasts alike.
