I have taken the plunge & purchased Frostgrave, however as I do not fancy building a frozen city & putting snow/ice all over my existing fantasy figures, I intend to make use of a stockpile of Ancient Egyptian ruins (courtesy of various Aquatic shops) & set it in a long lost Egyptian city. Also lots of very nice Crusader period figures for followers etc. As someone else on the forum said simply replace things like snowmen constructs with giant scorpions (this time of year Poundland starts stocking Halloween things like packs of insects, which hold:- spiders; ants; scorpions & grubs. All become 'giant' in 28mm.
So if your spell caster does get cold, send her over.