Small Business Tax Reform Act - Provides, under the Internal Revenue Code, for a ten-year carryover of net operating losses incurred during the first 10 years of operation of a trade or business. Authorizes a partnership to elect to close its taxable year as of the date of death of a partner, or provides that the taxable year may close only with respect to the deceased partner. Provides that the estate of a deceased spouse shall not be treated as a shareholder in a closed corporation electing taxation as a partnership. Increases the number of permissible shareholders in such a close corporation from 10 to 15. Authorizes grantor trusts and voting trusts to be shareholders in closed corporations eligible to elect to be taxed as a partnership. Directs the Secretary of the Treasury to study the possibilities for simplification of the last-in, first-out method of inventory accounting.