Wes - Long time since you have posted. This is something that can't be answered specifically as there are too many variables to include such as processor, memory, server activity, operational or non-opearational database.
However, I just did a restore of a 350MB database leaving the database operational in about 3.5 minutes. This is a Compaq Proliant 5500 with dual 450 processors and 512MB or Memory. Activity on this box is moderate so, processor and memory should not be a constraint here.
Don't know if that is what you were looking for but if you want other specifics, shout.
“He is no fool who gives what he cannot keep to gain that which he cannot lose” - Jim Elliot