Patudo, thanks for your input. You comment about 10x50 being popular back in the day seems so right; one only has to scan the 2nd hand websites to discover an endless array of 10x50 of all prices and styles. It is a pity that 10x42 seems to be the norm nowadays and only a few brands dedicate their efforts and resources to create a mid-range 10x50. For example, looking at Nikon's chart of roof binoculars which includes nearly 30 models in 7 different ranges, there is only one 10x50, the Prostaff 5, in the lower part of their optical performance range, no 10x50 Monarch 5, 7 or HG, let alone an EDG.
I've had a number of classic porros (JB, CZJ, etc.), but I've got mixed feelings. I love porros, really, from their shape (I like the way the hands curl around the barrels more comfortably than with roofs) to their optical properties, and while the EII and E(C) provide very nice views, my experiences with +20/30 year old porros were a bit of a disappointment performance-wise (E. g. I had a 8x30 CZJ multicoated Jenoptem in impressive condition that was simply trounced by a 100 € 8x30 Kowa YF; well, at least to my eyes). So I have grown a bit wary of the very tempting 10x50 offers of classic German/Japanese porros (there are so many nice looking ones on the German Ebay). I'm a big fan of porros, but the yellow cast on the classic models combined with the rigid plastic eyecups are not my cup of tea. And then there's the problem with the condition of such classic pieces (as you say, collimation, fungus, haze, etc.). This is why I find so sad that there doesn't seem to be a lot on offer between say a Nikon Action Extreme (I had the 7x35 and loved it, if not for the weight and bulk) and something like a Fuji FMX with its IF. It seems to be whether a 100-150 € or astronomy dedicated IF die-hard 1,5 kg instruments. Such a pity that there is no Kowa "IF HD" on 7x35/50, 10x50 or a Nikon "EIII". I had the Pentax FP WPII but found the FOV a bit tight and the eyecups just so large that they became uncomfortable for extended use.
Over last weeks, thanks to comments like yours from other members I'm making a list of candidates, to see if I can test or have some sort of first-hand experience with some of them, so just keep your comments coming, they are all more than welcome
Thanks again!