Wow indeed! That last model by Randy Cooper is quite special isn't it? I'm familiar with the others but not that one. How the heck would you get that on the wargames table? Thanks for the link!
Before you spend the kids inheritance though, have a look at this one too:
http://www.frontiermodels.co.uk/MARTIAN-TRIPOD-FIGHTING-MACHINE-p-16802.htmlAt 13" tall not too bad a size for 28mm and probably affordable to get a couple.
Mind you, that Cooper model is so special it might be time to tell the kids the bad news....