Ahhh... Interesting that the following statement will work perfectly:
INSERT INTO TESTVARIANT (ITEM) (Select Convert(money,(15)))
And SUM() still will not work with the datatype. I thought it would. In fact, I thought the whole point of Sql_Variant was that you wouldn't have to do conversions when you pulled the data back out of the column.
Well, lookee there. I learned something new today despite my efforts not to. @=)