Very cool... I wonder if the Splenda is the reason the crust didn't brown more... Do you know if Splenda carmelizes like sugar does??
Someone else may have to chime in here for a more authoritative opinion, but I'll offer my understanding. The sugar is present to activate the yeast, which Splenda seemed to do just fine. I did not think the sugar had anything to do with crust formation.
The various 'how-tos' I have read on doing bread in a pressure cooker have mentioned that you typically won't see the type of crust usual with regular baking. The cookbook I have says if you want that 'storebought' style crust, coat the dough with milk for the last few minutes of baking...
Also, I did this in a ceramic bowl as that's the only vessel I had that would fit in the pc. I need to get some steel, handleless pots or bowls, and I bet that would brown up the edges a little better.
Who knows? I don't need the crust, so I didn't worry about it too much.