As a new member of the LSB, I'm going to jump in here and say that it seems reasonable to me to create such a meta, and to make it legal in part headers. Having said that, while I don't personally have a whole lot of input right now, I feel that all values should be in some pre-defined unit.
In other words, I think we need to pick one single allowed unit to use for length (I would vote for LDU), and set in stone that that is the only allowed unit to be used in the meta. Software paying attention to the value can give the user the option of what units to display the information in (studs, LDU, mm, cm, etc., where studs would probably be the default length unit), but I don't think the meta-command itself should support more than one of each supported type of unit (length, area, volume, etc.).
Please note that I don't feel strongly about my point above. It just seems that the information would be more useful if it had a concrete meaning, as opposed to just being a string. But maybe I've just spent too much time thinking about BIM in my day job.
In other words, I think we need to pick one single allowed unit to use for length (I would vote for LDU), and set in stone that that is the only allowed unit to be used in the meta. Software paying attention to the value can give the user the option of what units to display the information in (studs, LDU, mm, cm, etc., where studs would probably be the default length unit), but I don't think the meta-command itself should support more than one of each supported type of unit (length, area, volume, etc.).
Please note that I don't feel strongly about my point above. It just seems that the information would be more useful if it had a concrete meaning, as opposed to just being a string. But maybe I've just spent too much time thinking about BIM in my day job.