Personally, I wouldn't group events with products, but that may be just personal preference. I see what you're saying about not having enough image from any one category to create solid categories.
Looking at your Flickr again, I would probably keep things fairly vague for now with categories of Events, Portraits, and Miscellaneous. (If you want to get artsy, I've seen people call the miscellaneous section "Potpourri") IMO, this would let you to focus on marketing to bands, weddings, engagements, etc but still allow you to display some of the other good images in architecture, cars, and products.
I don't think it is a necessarily a bad thing to have a limited selection of image on your portfolio, unless you are hoping to present yourself as something you aren't. I had a discussion with my hired wedding photographer a couple years ago after it turned out to be a complete disaster...to make a long story short, your portfolio should depict the quality of work that you are able to CONSISTENTLY deliver. I'm not saying to avoid showing only your best work, but if your current best in any particular category isn't a "WOW" image, I don't think you should avoid using it.
I understand what you are saying, but you and i both know every photographer is going to use their strongest images on their portfolio weather they are consistent or not.