In regards to crafting time, I think RAW is perfectly fine. As SK pointed out, this is a case where 100% buyback becomes helpful - just rent an item to round out your equipment list and go adventuring whilst you wait. No need to sit around on your duff in the DWI.
The only issue here is that, if I'm reading the commissioning rules correctly, you have to pay up front. So, to temporarily replace an item while you have it upgraded, you have to have the crafting cost + temporary item cost in available funds. Unless I'm misreading and the up-front charge is different for crafting than commissioning new?
I don't know that I fully object to that, since if there were no cost whatsoever to crafting, there's no real point in forcing the real-time delay. I've been under the impression the whole idea is that sometimes, an adventurer should have to make a choice which isn't particularly easy: take what's on hand, leave something behind and go out without it, force the party to delay, or pass on the purchase until a more convenient time.