You don't see flangers for a reason
The problem with some circuits, and that BYOC one is a prime example, is that even with a PCB and all the advantages that gives you when it comes to doing the layout (i.e not limited to horizontal tracks and links, ground planes for close connections from anywhere, traces in any direction or orientation, and often multiple layers), that board still needs a 1590BB box. Because neither myself nor Miro will do layouts with standing resistors, along with the physical limitations of stripboard and the number of nets in a typical flanger circuit, to do that in vero format for us would end up needing a box the size of a small DVD player and for that reason alone I would always use a PCB to make something like that.
There are a couple of flangers that I am looking at and will probably do at least one at some point, but that's only because it's very similar circuit to some of the chorus pedals we have on here like the Small Clone and Boss CE-2, so I reckon I could probably get it in a 125B box but certainly get it in a 1590BB.
I have said at some stage when my to do list is depleted I will start doing bigger layouts but less frequently than we do them now, but even then I'd be unlikely to do a layout for anything, especially DIY effects where good PCBs are readily available. I'd be looking at some classic unobtainium like the Flange With No Name, TZF and similar that a lot of people may want but they simply have no way of getting hold of. I think circuits like that will be worth doing (assuming I can get the schematics of course) and valuable additions to more people. The boxes will end up huge, but then the originals were too