im sure you can get a sleeping bag.
fo3 had a mod that gave you a sleeping bag, to use anywhere you want.
wanders edition mod made you eat sleep and drink, and it was cool. not annoying....
so don't worry

This. Even if there isn't a bedroll item, in New Vegas you can now sleep in owned beds, and only get a karma hit. Also, I'm sure they put mattresses or beds, or cardboard beds regularly throughout the wasteland and "dungeons" taking into account this new requirement. Even in FO3 it was easy enough to find beds or mattresses everywhere. I don't see this as a problem.
If the rate is going to be realistic (in respect to in-game time rate) then it will become extremely tedious to constantly eat, drink and sleep. Much like being a vampire in Oblivion, the feeding eventually becomes an annoyance to the point you just cure yourself. Constant notifications would also be a poor choice for me personally. I dont want a pop up every X minutes saying time to eat/drink/sleep.
I would only want a pop-up if the hunger/condition was reaching dangerous levels. If you only have to sleep say 4 hours once every 24-36 hours, its not a big deal. Say you start getting penalties after 48 minutes with no sleep, and then start getting more severe penalties for each additional 6 hours without sleep. Like someone else said, 48 minutes is about the length of time to run a dungeon or quest, and assuming you also have to drink and eat once during that period as well, all it means is that on hardcoe mode you are going to have to think more about your actions and plan ahead. Probably the preferred method of exploration will be picking a central spot or site that can fulfill your survival needs (either a settlement or a building you have stocked with supplies that has a bed) and making sorties out from it. Using Fallout 3 as a theoretical example, if it had hardcoe mode, maybe your base of operations would be Megaton, and you would stock at least 2 days of food and water each time you left, catch a night's sleep, then go explore Springvale fully, then return. Catch some shut-eye, resupply, go check out the Superduper Market, return. Etc. Etc.
Really, you'd just have to be careless to die on hardcoe by dehydration or starvation. Even if you want to just explore without returning to a central spot all the time, just make sure you have a lot of supplies, and then divide them by 2. Say you have 6 days worth of supplies. Now you know you can explore for 3 days, and if you haven't encountered fresh supplies or a new settlement, you know to turn around and use your remaining 3 days of supplies to make it back to your starting position.
I'm not sure what will happen when your sleep meter runs out. You shouldn't die from this, just collapse and sleep it off, but who knows. Maybe New Vegas has some of the non-standard game overs from the first two Fallouts, something like "Exhaustion overcomes you, and you slip into darkness. Maybe an animal preyed upon your sleeping flesh, perhaps a raider found an easy mark. Regardless, you never awaken." Unless the penalties get really bad before you pass out, I don't see how just sleeping it off and waking up again in a few hours would be a suitable setback for neglecting sleep.
While I am looking forward to hardcoe Mode, I was really just hoping for stimpaks dealing health over time and ammo having weight and such. The eat/sleep/drink requirements make sense but did they really have to make your weapons more prone to breaking?
hardcoe mode should've brought the difficulty more in line with FO1&2, not the S.T.A.L.K.E.R. games!
I don't really agree with it, but if weapons do break down more easily on hardcoe mode, it's not such a big deal. It took a long time for the condition meters on a fully repaired weapon in FO3 to go down to the point that they broke. Keep in mind that we now have Repair Kits in New Vegas, and you won't have to find another version of the same weapon to do repairs. Again, this will just emphasize planning your actions before heading into the wastes all willy-nilly. With ammo having weight, you are probably going to just focus on 2 or 3 weapons at most. Invest in the Repair skill, or get your weapons repaired in town before heading out. Also, just like food and water, no real survivor of the wastes would consider heading out without a repair kit for their weapon.
I can see it becoming a common practice for hardcoe Mode characters to carry a pistol, a rifle or assault weapon, and a melee weapon for backup if you run out of ammo or your weapons break.