I found a list of essential oils on wikipedia: http://en.wikipedia.org/wiki/List_of_essential_oils
Some of them seem to indeed be toxic. Other interesting info is that some are extracted via solvents, which might not be safe.
But, I also came across several more internet sources that had some yummy sounding flavors:
1. We've already ordered from here: http://www.faeriesfinest.com/ They seem to have some nice flavors and were easy to do business with. Although their PayPal integration was a bit odd. That is, they are not integrated at all, but if you PayPal them money they will use that to pay for your order.
2. https://www.lorannoils.com - LorAnn Oils seems to have a great selection, good prices, and smaller containers (which is a good thing while we experiment). I've seen mention of them in forum posts past. I think my next flavor order will be from here.
3. If you are interested in organic oils - http://www.naturesflavors.com/default.php - Natures Flavors seems to have a bunch of interesting options.
4. American Spice - http://www.americanspice.com - seems to have a wide variety of flavors too
5. Sutton Bay Spices - http://www.suttonsbayspices.com - seem to be reselling someone's stuff from the feel of the site, but again an interesting assortment of flavors (not to mention a wide variety of hot sauces)

So, LOTS of options! I think the next can will be cherry - using the cherry we got from Faerie's Finest. We'll get this one started, maybe Tuesday evening.
I'm not sure how/where I will record successful SnusX recipes. But, I'm declaring the "Berry Blend" recipe using the recipe posted earlier a success as documented. I was going to increase the flavor a bit, but, after having 24 portions of it - it is good how it is.
EDIT: I have started a "Custom Page" for SnusX recipes. This can be accessed by entering the "House of Snus" and clicking "SnusX Recipes" in the side-bar.