One woman in Toronto removed an old hot water radiator that was under a counter and can't find anything small enough to take it's place.
We went digging and came up with two that would fit. Myson is a company from Colchester, Vermont that makes hot water d?cor radiators from 6 inches to 79 inches in height, some that look like baseboard radiators, others that stand like tall columns -- and of course the 18 inch one that our viewer needed. These modern radiators use fins on the backside, in different configurations, to give off more heat than the old cast iron ones because there is more heated surface to warm the air.
It is a bit hard to tell, but one of these pictured radiators is twice the cost of the other, so check the price tags as well as the design book. You might even want to check out their Low Surface Temperature radiators for kids rooms. The heat is in the back, not the front.
Of course you can also find a wide variety of electrical heaters that could fit into difficult places like those from Dimplex Canada.