Yes, the Cologne Cathedral nave organ does look impressive and is in an acoustically advantageous position.
Apparently, they were not allowed to attach the organ to the nave wall or in any way alter the fabric other than to make holes in the vaulting to accommodate the supporting cables, which are supported from large steel girders in the loft. The organ simply rests against the nave wall.
Strangely, it has a carved wooden clown-like thing which can be released from beneath the Positive section at appropriate moments! I'm not sure of its significance (probably some local custom or personality?), but am very surprised to find such a thing in a Roman Catholic cathedral.
Incidentally, I contacted Klais to see if they had produced a book (along the lines of 'Ein Hauch, Ein Ton' - see above posting - which I purchased a couple of years ago) about the rebuilt transept organ. They have not, but I believe are trying to persuade the cathedral authorities to do so. In the meantime, they were kind enough to send me a leaflet providing certain details and plans of the revised instrument - unfortunately in German only, but nevertheless very interesting. Would that it were possible to obtain such things for all organs!
The Vox Balenae 64' (voice of the whale?) is derived from the new (wooden) Principal 32', and has no pipes of its own, which prompts me to wonder why, if this type of resultant requires only separate pallets and some extra wiring, such stops are not included in all 32' organs!