Some random thoughts/opinions I have had on this subject since I briefly considered doing the same thing as my area doesn't seem to have any PV-specific retailers at all.
First off, I would also advise against a mall kiosk. Those damn things have already left a bad taste in the mouth of many potential customers and the rent might make the whole thing cost-prohibitive anyway. If you want to make a profit, a business you can run out of your own home with no permanent "storefront" is probably your best bet, at least until you establish a nice customer base.
I think the idea of working with some local gas stations is a better idea, particularly those stations that are 1) high volume and 2) have more of a blue-collar clientele (i.e., sell a lot of cigarettes). You might also consider approaching some of your local tobacconists but you may also get some substantial resistance from them.
Pick one or two proven reliable and cost-effective models to focus on. At first blush, I would think a standard 510 and a compatible "upgrade" like the Riva or the eGo. Personally, the black model Riva would probably be a good "flagship" model to build your business around. It has conservative good looks, has been proven to be pretty reliable, and you can also sell some bling models (like the all-pink and the stainless steel). Also, sell at least one line of solid
ejuice in at least 10 or so flavors with at least 12, 18 and 24mg strengths in at least a couple of different sizes.
What seems most critical to me is acknowledging the fact that any quality PV just has a substantially higher learning curve than analogs. You will need to
TEACH your customers how to use one of these things so that they feel comfortable and confident severing (fully or partially) the umbilical they have between Phillip Morris/RJ Reynolds/etc.
To that end, here is what I would strongly recommend. Produce a series of videos, featuring yourself preferably, that espouse the virtues of PVing in general, and explain the basics of using the products, refilling carts/dripping/cartos, cleaning/maintaining equipment, battery life, juice strengths, etc. All of these videos should feature the specific products you sell. These videos should be at least modestly professional (i.e., better quality than your average YouTube review video shot in someone's bedroom). Burn these videos to CD-ROMs (which are dirt cheap) with a decent label on them. They can
learn so much more about what it is you are selling and why they should buy it from those videos than they can from listening to you in person for 3-4 minutes.
So, picture this. You set up a table outside of a high-volume convenience store. You have demo products that people can try and, even if they don't try a demo (after all, they may just be a loved one of someone else who smokes), if they show any interest at all,
make sure they walk away with a video CD, a price list and 3-4 of your business cards. Out of pocket for the CD and business cards per potential customer will be very minimal.
Be willing (and make it clear to anyone that you are willing) to do in-home demos Pampered Chef-style or host potential customers in your own home if practical.
Have a website that also includes the price lists and hosts the same videos.
Make sure your prices are at least in the ballpark of what people can buy the same stuff online for. People will pay a premium for the personal TLC that you provide, but how long they buy from you rather than Liberty Flights or someplace like that will depend on how much of a price difference there is.
Again, this is just what I came up with while considering the same concept a few days ago.
