After several weeks in making, the first version of the SDR Mark1 schematic is finally here. Look at the SDR Project page, click "Schematic" at the index on left.
It may be a right time to apologise for the statements made earlier as "simple", "easy" etc! :))
While in fact its not too complicated considering what it is about, I ended up with way more components than initially planned.
On the other hand, it has no cut-backs anywhere, so I can state that it is as good as my current knowledge of SDR design allows me to create.
Now to the PCB layout and then we shall see if it performs as supposed to!