Monte A. Jackel & Gary R. Huffman (both of McKee Nelson, Washington, D.C.) have published Partnerships Under the Proposed Domestic Production Activities Deduction Regulations, 110 Tax Notes 251 (Jan. 16, 2006), also available on the Tax Analysts web site as Doc 2005-25322, 2006 TNT 11-19.  Here is the abstract:

The authors describe the pertinent provisions of the proposed regulations under section 199 as they apply to partnerships and partners. The proposed regulations will be extraordinarily difficult to apply in this context by taxpayers, and it will be equally, if not more difficult, for the government to monitor taxpayer compliance. That is due to the interaction of complex cost allocation systems mandated by the regulations to the provisions of subchapter K, particularly the ability of partnerships to specially allocate items of income, gain, loss, or deduction among the partners. In addition, the failure of the regulations to apply partnership aggregate concepts, in other than very limited cases, will undoubtedly hinder many bona fide business activities conducted through partnerships, particularly when either the distribution or the management function is divided between the partnership and one or more of its partners.