Not really. Most of the Ogrdu Hem encountered in the comics would be around the size of a gallon milk jug in 28mm. It's implied they can grow pretty much indefinitely if empowered/fed, but they're usually dispatched before that snowball can get rolling. Totally gameable as a "boss monster". IIRC there was a Kaiju-sized one in the "Black Flame" arc, but that's the only really huge one I can recall (though I haven't read all the stories yet.)
Just yesterday I bought one of the 'big bumper' volumes of BPRD, with stuff I hadn't read yet, including that Black Flame arc where Katha-Hem showed up. I think my reaction would have been pretty much like Professor O'Donnell's.
There are smaller Ogdru-Hem, like Sadu-Hem, the 'Conqueror Worm', the Lovecraftian 'twin brother' that Abe and Daimyo killed, etc. But since the Ogdru-Hem
really started to wake up, many have been absurdly massive. Cyclopean, even. Like the
Salton Sea monster, the O-H in Scotland and Russia, and so on.
Not to mention all the smaller monsters and subsequent mutants and things. Hence the 'Hell on Earth' subtitle. And it'd be very difficult to cover
that up.
Gaming-wise, I agree that's it'd be a great setting for wargames of various scales. The big Ogdru-Hem would be a tad unwieldy (and those games would largely boil down to whether you can survive or stay sane or unmutated long enough to chuck a nuke or a Liz Sherman at it) but conversions of the big tyranid kits could be used for smaller hems and other gribblies. Although the basic models could still seen too... 'conventional', in ways. The bigger gap in the market, besides readily-available BPRD members, might be suitable representations of frogs...
I think I have some of those BPRD horrorclix about here meself, though. Time for a hoke.