This is the reason you SHOULD use projects*, even for all assets if your stuff is under same project root then maya will know where to find stuff no matter what the directory is as long as the file was loaded form within the project. Also it makes archiving things MUCH easier (please note for any media producer who does not archive their stuff properly ans with very good care is throwing away 1/3 of the value of ANY project, so its like throwing money down the drain).
In any case just a heads up for you, if you do this anyway there is a command that will save yourin the future (for example because you wanted to open the files in a macintosh system which can NOT have drive letters). Which is primarily mean to mitigate just this problem, and its called dirmap.
- yes i know it's not always convenient, but it sure as hell is convenient, backup, versioning and archive time. So its a bit of trade of between doing right for the big picture versus doing the thing that is easy right now.