Jan Simon

If the EXIST test would be omitted, procArgs could even *create* variables in the caller. But this would be dangerous and would confuse the JIT compiler: "assignin('caller', 'RANK', 1)" collides with the Matlab toolbox function 'rank' (at least in Matlab 6.5 and 7.7). Therefore I appreciate that you've included (and updated) the EXIST test.
You are right: debugging is not impossible. ASSIGNIN and EVALIN can obfuscate a program and predicting the effects can be really hard. But to be honest: one can write obfuscated source even without ASSIGNIN! procArgs with some good comments can be much better than a hard coding without comments.
Rating: H1 line, help, example, version number, name of author: exsiting. Function works, is useful and usable. I personally prefer hardcoded access of variables and this might be a question of taste.

The function starts with overwriting VARARGIN - please remove this!
The help section now mentions, that the -find option works on Unix only. But a check in the function (if ~isunix, error('-find works on Unix only'); end) would be useful.
Please update the file information on the FEX: This function does still not run under Matlab 5.3.
The help section is still hard to read (for me) due to the formatting. A H1-line would be helpful (see LOOKFOR command).
Some simplifications are possible, e.g.: "numel({d.name})" equals "numel(d)",
"to_do = strncmp( varargin, '-', 1 );
neg_queery = ~to_do&strncmp(varargin, '~', 1 );" is easier as: "neg_queery = strncmp(varargin, '~', 1);".
Comments in the source are recommended generally.
I really like the idea of expanding DIR with a filter for numerical indices.

In contrary to the file informations above, new_dir does not run on Matlab 5.3.1 (and 6.5 also), because the DIR command does not reply the field 'datenum' for this versions.
No meaningful H1 line, the help text is long and exhaustive, but hard to read (please insert a space after the %, limit the line width, use some empty lines to divide sections). A lot of examples are given, but some crash: There is no "-regexp" flag for the FIND command of Windows XP --- perhaps your function is written for Unix only?! If so, please mention this.
No comments in the source. The initial section for debugging is useless for FEX users.
If updates of this files are submitted or searched, it is helpful to mention the full name of the author and the exact date of submission.
Working partially on WindowsXP, but not under the claimed Matlab version.

Useful function.
Beaware, however that the times return by this function do not necessarily match those return by the MATLAB dir function. This seems to because Windows add an hour when reporting the time during daylight savings time (even if the file wasn't created during daylight savings time. See http://www.mathworks.com/support/solutions/en/data/1-1YLPX9/index.html?product=ML&solution=1-1YLPX9.)
MATLAB however does not do this.

I this function appears to return the Windows time. So I have run into problems when using the two functions together.

Works perfectly in the current release R2009b