I got this in my inbox last week and was curious if anyone has used it:
http://www.protomold.com/Design_Tips/UnitedStates/2007/2007-03_designtipvolume/default.htm?ls=CP07
They are claiming injection molded parts as quickly as next day. Smells like BS…but was curious if you have had any experience with them.
My company has used them for some rapid prototyping a couple of years ago. Next day is possible but unlikely.
I would expect a turnaround on par with an SLA.
They could only do smallish parts (6"x6") at the time, simple open-close tools, maybe a hand pick-out for an undercut. Not sure if they have improved that capability.
The concensus was: They don’t suck, but you can learn about as much and can get a more complex part with an FDM.
I’d be scared if my parts were made that quickly 
Somethings take time for a reason and I wouldn’t want a 100K mold to be rushed.
But if you are looking for quick ways to turn get a limited run on parts, RTV molding is fast, usually 5 to 6 days and much cheaper.