First I'd like to say that I've read all 7 pages of this thread and found that Jake has an attitude towards business that other vendors should look to as a model. Your willingness to be open about your product shows your confidence in it; and your request for feedback in a public forum is something I've rarely seen (since you can't really control what gets posted). Even if your prices were considerably higher than others I'd still be more likely to order from you just based on your candor with the members here. It makes you seem more personable instead of being just a few faceless drop-down menus and a bunch of numbers or text.
Now, to my point. I'm just now delving into the DIY liquid game, but have been making my own mods for a while now. Based on my experiences trying to find parts and tools needed to build them, I must say that the more you can offer in one place the better. One of the biggest reasons is shipping cost. I go to one site for batteries, one for this part, one for that part, and countless others for the rest.
The whole eCig liquid market is still fairly young as well as small, and you could take advantage of that by carrying everything one would need for DIY creations. I mean from protective gear to storage and everything in between, including flavorings etc.
If you don't want to give up your proprietary recipes, don't, and no ill feelings for not doing so. The base concentrates would be enough, if people wanted to modify a flavor they could and should buy the original formula and work from there. If you have your own custom made bases (like banana completely from scratch) and want to keep it secret simply re-sell others. If I find a flavor of yours that just can't be beat I have no issues with buying it for use in modifying others. Maybe consider selling them without nicotine for use as a PG/VG base.
Anyway, to avoid being even more wordy I'll just say kudos to you and your exemplary business ethic.
From the bottom of all of our hearts at Nude Nicotine, thank you! We really try to be as transparent as we can be with our chemistry and business as a whole as we can be; glad others view this as the honesty and passion we truly have toward this industry and not just a marketing ploy.
I regards to an interesting point you had about flavorings:
-I am in the process of packaging our flavorings to be sold as concentrated-flavors-only. And You bring up a VERY interesting point; one that I was discussing with a colleague the other night. We really would like to keep the flavors proprietary, as to release them in premade 'blends' - i.e. 'Banana Cream Pie' concentrated flavor, rather than the banana, cream, and other flavors separately. Do you personally see a market large enough to do so? For preserving our chemistries, this is the best move for us; but we want to be keen to how the public would be using our flavorings.
PG and VG are to be added to our inventory in the next few days, as well as a few DIY items as well to start

Specifically for the PG and VG, what sizes would you all like to see added? We had thought 500mL and 1L aliquots would be best.
Got my NudNic 100mg, nice! This is what I had expected good nic to smell and taste like. Had some bumpy experiences with smelly stuff, but this is great stuff.
Jake, Australia is crying out for this stuff, I am going there for an extended period and the options are getting Chinese nic, or only 48 or lower or smelly stuff there.
The market is crying out for it.
Glad you're enjoying it

Did you dilute some down and do an unflavored taste-test? Hmmmmmm..... this gives me an idea for an AWESOME promotion.
Re: Australia shipping - our merchant contract at the moment only allows for shipping within the US for nicotine products. For the future, I see two foreign markets in our attack plan: Australia and the UK. Know that this site in our mind as a plan within the near future; however at the moment we cannot ship our nicotine-related products outside of the 50 US states

It really pains me not to be able to offer this service at the moment because yes, I see a MASSIVE market in both places. We have had to turn down numerous international contracts that would have allowed Nude Nicotine to expand immenslely