I have a few comments:
1) Post this question on the SAS/IML Discussion Forum in order to solict advice from other SAS customers: http://support.sas.com/forums/index.jspa

2) I have done (B) many times. It is my method of choice, but then I know both MATLAB and IML. I have also supervised a graduate student in a large-scale project of converting her advisor's MATLAB code to IML. She converted about 6,800 lines of code over the course of the semester. Yes, it is often 1-to-1 conversion, but it depend on what MATLAB functions are being called.

3) The choice between (A) and (B) depends on the time you have, the expertise you have, and the complexity of the algorithm you are trying to convert.

4) I once had bookmarked a "cheat sheet/reference sheet" that had a comparison of MATLAB and IML syntax, but I can no longer locate it!