I have not been able to find a report that provides by category and total for a specific job:
Budgeted cost
Actual cost
Variance (+, - or $0) of budgeted cost less actual cost

The closest I have found is the Direct Cost Analysis Report but it appears to calculate the "percent complete" based on actual/budgeted cost, then it uses that percentage to calculate and "adjusted estimate", and finally it determines the variance based on "adjusted estimate" less actual cost. This report also does not include any categories in which the variance is $0 or that has $0 costs incurred. I can go into "Estimates" and adjust the % complete to 100% for each item but it is very time consuming and will not allow any changes to the % complete for categories that have not incurred any cost.