I have the ZenDesk frame and it's pretty great, they are also more like $650 as there is a $100 coupon for signing up to their newsletter. It's obviously not a great fit for you due to the minimum height but I did just want to make a comment regarding the design here.

The ZenDesk legs are a two piece assembly where one half retracts into the other. In theory the minimum desk height is equal to about half the max standing height. For the ZenDesk design to get down to like 30cm you would need to have more parts in the leg assembly which sounds pretty difficult from a design and materials standpoint, especially if you want to retain the lifting strength.

I think it's going to be very expensive if you want a unit with legs that go that low.

(I'm not an engineer, I am probably be completely wrong)