Seems to be a bit of confusion here. Pressing T (in Aspire and VCarve) accesses the Size tool which is a different thing from the Create Text tool which doesn't have a shortcut key. I think the mention of T was in reference to the icon itself rather than a key.
The size tool can do part of what Mike is looking for by using the percentage option. That way it will enlarge the individual items by that percentage rather than setting the whole selection a fixed size as happens when entering an exact size.