specify a dependency on dev code

I would like a way to express in an info file that a module depends on a particular version of another module OR that module's dev branch. For example:

dependencies[] = somemodule(>7.x-1.0-alpha2, 7.x.-1.x)

That would mean that the dependency is satisfied by any version greater than alpha2 or by the dev version. Granted, there would be no way to know if the dev version someone has installed is actually more current than the alpha version, but the burden would fall on the site admin to make sure that a more current dev version is in use.

Without the ability to express "or the dev version", the site admin has no option to pull code from drupal's repo, since such code will not include a version number. (Current workaround is to manually add the version info.) Another possible way to express this...

dependencies[] = somemodule(>7.x-1.0-alpha2, NULL)

In other words, the dependency is satisfied by somemodule greater than alpha2, or by a copy of somemodule where the version info is not included in that module's info file (presumably because it has been pulled from the remote repo).

Even better would be the ability to specify a required version, but I don't know how hard something like this would be to implement...

dependencies[] = somemodule(>7.x-1.0-alpha2, >d1227523bcd09ab974551edf6435ebde01beb7c1)

Thanks.