Okay, here's what I'll say: You're going to be selling photos pretty much at a maximum resolution of 1024x, so while most photos benefit from being shot a bit large and then being reduced, there really is no reason to shoot larger than 1600x. (What I'm saying here is entirely for web work.)
You can take very decent photos using fill and bounce. Take a look at my newest gal, Lorena, shot in a hotel bathroom using nothing but fill and bounce flash:
Don't let your photographer talk you into buying his dream camera for him. I use an Olympus C-3000, C-3040, and C-4040 (all very closely related cameras with very similar controls). I'm sure there are other brands, but this is the brand I would recommend, because only it and Nikon (more expensive) offer you the ability to use bounce and fill on a TTL-metered basis (the flash is controlled by the camera based on metering the light from the actual image, rather than some sort of calculated estimate).
Hope that helps. I'm sorry Aaron was washing his hair. Lucky for you, I just got done flossing my teeth and rearranging my sock drawer, or I wouldn't have been able to help you, either.