Having just purchased a few straight razors for the first time myself, I will have to agree with everyone saying DOVO
Reasonable price for good quality, recognizable brand to potential customers, and you can keep them in stock...
That said, I agree with the folks saying you need to know what you're getting into before you make that jump. My father has one of those sharpeners you reference and I wouldn't put my hunting knife to it, much less a razor that's going to be on my face. It won't create the correct bevel angle, it's far to coarse even with the finest belts, and it will never create a consistent edge. Not to mention you'll take off WAY too much steel each time. With my very very limited experience in this, I would say that you should first start shaving with a straight razor yourself and learn to hone it as well. If I were a potential customer, I would assume that the storefront that I bought a straight razor from would be able to hone it. If you aren't equipped or skilled enough to do this for them, that makes for a fairly awkward explanation to a patron that just spent >$100 on a cherished razor from you.
You noted that you were surprised with the nuances in the wet shaving community in regards to razors themselves. These particularities span far more than just the hardware and it's a fascinating discovery process - one that I am enjoying wholeheartedly. That said, I would not feel comfortable offering products to my customers that I was not intimately familiar with in every way, and learning first hand is likely the best way to gain this knowledge.
In the meantime, a good offering that might require a little less in-depth exploration may be safety razors. The added benefit is that you'll have customers coming in from time to time afterwards to buy new blades in addition to your soaps, etc.
Food for thought. Quite an interesting question though, I'll keep watching this thread to see what other good advice you can get from the seasoned members that I can use myself :)