Mystery solved!

[chirine ba kal]

A while back I asked if anyone had seen or heard of a very neat pyramid model that I found in the local game shop. It turns out that is't not billed as a 25 / 28mm model at all; it's a 15 / 18mm from Blue Moon, their catalog 15 HOR 212A in their 'Horror' range. I think it works just fine for 25 / 28mm; the entrance doorway looks right, and the mummy you get looks pretty durn tall for a 15...

And thank you all once again for your efforts, too!