I believe that in the current version of SL, the textures for your avatar are "baked" by your local graphics card and then uploaded to the server where they are seen by others. It would appear, from evidence, that parts of the prim model are treated in this way too (I experimented on this with a friend last night - with both of us wearing the Ruth shape and skin, I was about 2 inches shorter than her when using ForceWare 91.xx, but the same height when using ForceWare 93.71 - and both of us, myself and her, saw me this way).
I would like to encourage LL to change this and use a software baking routine which would be part of the SL client and work the same way on all machines.
The main reason for this is that, for example, if I wanted to play a pixie or a child or something else small, I would do better to reinstall ForceWare 91.xx to get access to the smaller sizes caused by that driver's foibles. A dancer at a club could wind up being told that they need to use a particular graphics card and (possibly legacy) driver because it generates sexy rendering artefacts*. The same could apply to models, or furries, or anyone wanting to have the best possible appearance in SL. People who might not be willing to essentially sacrifice a fairly major part of their computer's configuration for the sake of their SL appearance are just out of luck.
I would therefore ask if it'd be possible to standardise the baking process as part of the client, or at least offer the option to use a software baking process where these foibles can be configured by the user to match those of the graphics card which is best for each particular purpose.
* I will forever thank SL for allowing me the opportunity to use the phrase "sexy rendering artefacts" in a sensible sentence.