Well, it depends on the kill -- beheading most creatures in combat will lead to a short wait time. If you stick them in the liver and wait, you might have an hour or so. In the end, this is why we have on the short list of things to add "Vulnerability Attacks". This will basically be hooked into the wrestling interface when that goes in -- once an opponent is straddled or otherwise under control, you can slit their throats or strangle them etc. Creatures have circulatory systems, so pulse checking will work as a diagnostic often times. The same holds for respiration.
Certain nefarious deities will be able to barter with souls. If you have the power and are sufficiently creepy, then why not? You know, it might sound far-fetched to say the player can do these things, but this particular one I planned for -- instead of just having "intelligence" and "wisdom" etc., every creature currently has an array of souls in its body (so multiple souls as in possession is permitted), and each soul stores skills and mental attributes (later personality as well). Souls could be moved to items (for intelligent swords, etc.), or moved into a demon's (Demon's) little magical pouch to be used as gummy bears later in the day. Don't let soul-shredding baddies make a meal out of you.
Incidentally: I'm on my new computer! And I don't have my FTP/Website problem anymore! (On my previous computer, the Bay 12 site was blocked -- even though I could go everywhere else -- I wonder how long it will take for Stanford to decide I can't come back here. I think they want me to do math ). It's amazing how much software you realize you need once you get a fresh machine. I'm slowly downloading AIM on my 56K right now, although I'll have to move the monitor back to my old computer to get my password. Uck...