With prices being so much higher in the gold auction house in hardcore, I think it's only a (short) matter of time before Blizzard realizes that not implementing a RMAH for hardcore is a big mistake to their profits. They'll make you jump through whatever hoops necessary to cleanse their hands of what happens if their servers cause you to die and lose all the real $ you put into RMAH purchases.. but I'm sure it'll happen eventually.
As for leveling the BS and rolling vitality gear.. I think you're better off just buying +vit gear from the AH early on. You know what the cost is, and there will be plenty of deals. The BS is a crapshoot and still costs a decent chunk of gold compared to what the AH has available.
Remember.. the stash is just as important for keeping high volume/low price guaranteed sales going on the AH. I always tend to price my *very* good items high and my decent items low. This ensures that I hit the jackpot every now and then but that I also maintain a steady flow of income. I'll keep 2-3 high priced items on auction, and the other 7-8 are priced very low, between 2k-20k, to keep money flowing.
In hardcore, unless it's a weapon, if it doesn't have vitality, I don't even bother with the AH. It gets salvaged.
Here's my list of what I look for:
1. If it's a magic (blue) item and has vitality+str/dex/int, I'll sell it for cheap (2k-4k), and it is gone quick. If it has a socket, it's easily sold at 4k-6k.
2. If it's a rare (yellow) item and has vitality+str/dex/int, I'll sell it for cheap (5k-15k depending on stats), and it's gone quick. If it has a socket, it's easily gone even after adding another 10k-20k to the price.
3. If it's a rare (yellow) item and has vitality & str/dex/int & magic find/resist all & socket, that's the sort of item you price high 75k-500k+ and wait to hit the jackpot.
4. If it's a level 60 item but has "level required reduced by xx", you can usually sell this for quite a bit as there aren't many great items available to level 45-55 guys.
5. Boots with +% movement speed always sell fast.
6. If it's a weapon and doesn't have a socket, it's worth much less.
7. If you're selling a weapon and it has a socket, stick a ruby in it so the DPS displayed on the AH menu is higher than unsocketed. Sure, it'll cost you a ruby, so only use one that you definitely don't need. If the weapon has a high dps for the level, vitality+str/dex/int, and a socket.. you can make some big money. If it's a monk fist or 1hd crossbow with +life added per hit in addition to the other good stats, that's quite valuable.
8. If it's a legendary and has fantastic random stats (some are fixed and some are random), it can be extremely valuable. I have Lut Socks (great MF boots as they have MF/GF/Movement speed as fixed modifiers) that have +vitality, so that's huge.