Donald T. Williamson (American University, Kogod School of Business) & A. Blair Staley (Bloomsburg University, College of Business) have published Are the Proposed Timely Mailing/Timely Filing Regulations Timely?, 108 Tax Notes 597 (Aug. 1, 2005), also available on the Tax Analysts web site as Doc 2005-14776, 2005 TNT 147-25.  Here is the Introduction:

On September 21, 2004, the IRS released proposed reg. § 301.7502-1(e) and (g)(4), "clarifying" rules prescribing when a tax return will be considered filed for all purposes under the Internal Revenue Code, including tax return due dates and statutes of limitation for amending returns. In attempting to clarify that only registered or certified mail constitutes sufficient extraneous proof of filing, the proposed regulations may well violate the intent of Congress in enacting the "timely mailing/timely filing" rule of § 7502 and emasculate rules under § 7502(f) that permit certain private delivery services to substitute for U.S. mail for purposes of the timely mailing/timely filing rule.

This article examines § 7502 and the conflicting judicial interpretations of the timely mailing/timely filing rule that led the IRS to conclude that the proposed regulation was necessary. The article points out an important piece of legislative history to § 7502 that directs the IRS to accept evidence besides the U.S. mail as proof of a return’s timely filing, which is contrary to the proposed regulations. The article also shows how the proposed amendment to reg. § 301.7502-1(e) would render the option of filing returns by private delivery services, specifically authorized by § 7502(f), a trap for the unwary. For those reasons, if the proposed changes to reg. § 301.7502-1(e) are made part of the IRS business plan for the next fiscal year, those changes must be revised immediately.