Hi, not sure if this will add to the original query or not, but I too have a home-made version of the Happykeeper floor. It's a fairly recent introduction but so far, so good:
This spring I used up some nice, clean timber which I've had lying around for a while and made a 4ft "trough hive" (takes BS frames, or top bars if I'm feeling radical). The cost of 4ft of stainless steel mesh for the base, and the vulnerability of using that much plastic mesh, made me look around for alternatives. In the end I created a quick, cheap, home-made version of the Happykeeper floor. It consists of frame-width plastic tubing, about 2.5mm apart, not mounted flush with the floor but simply hung on nails so that the edges don't quite meet the sides of the trough. Not enough gap to let much through (and certainly not bees), but it has a couple of advantages. Firstly, any mites that tightrope walk their way along the top of a tube can't actually get back up the sides of the box, because the hanging tubes don't quite meet the sides. Secondly, I can de-crud the tubes quietly and quickly by gently rolling them (they are loose enough to roll out slightly bigger bits of wax etc. without disturbing the bees). Any stuck bits of propolis or wax or whatever are easily dislodged, or can be cleaned off from below. The fact that the tubes don't let much light through seems to make the bees ignore what's going on, as if it was a branch moving or some other minor event.
This, for me, is an improvement on mesh which tends to bung up with bits despite the efforts of the bees to keep it clean, and requires a bit of maneovering if you want to clean it. My propolis-loving, prolific Buckfast crew also seem to delight in glueing up their mesh whenever possible, somewhat negating the purpose...
As it turns out, like Bird-dog, I find the bees tend to keep the tubes very clean, so I don't really have to move them after all. The hanging tubes do have another (possible) use though: I was worried about moths possibly squeezing in between, but the slight movement of the tubes and the steep upward climb to get in (and easy defence from above...) seems to have deterred any gatecrashers.
If I want to look at mite-drop, there's a slide-in floor underneath, which accumulates rows of bits from between the tubes (and, in theory, mites, although we haven't been bothered with them recently), so the fall-through process works. It was very cheap and quick to create, and I'm happy with it so far.
Whilst the Happykeeper hype about ventilation, and better insulation than wire mesh, is likely true, I wouldn't get hung up about the "eliminates varroa" claims, which are clearly cobblers. The best one can hope for from an open type floor, IMHO, is a clear indication of mite drop either from month to month, or following treatment. Still, the tubes are OK for me for the time being, and the bees have accepted them without problems. If you're in the mood for some simple home-made solutions to housing bees, then so far I can recommend it.
Anyway, I've hedged my options - the whole tube floor thing can be removed easily and replaced with mesh if I change my mind!
GB
