Flickr has a photo pool for the 100mm Macro, you can find a lot of non-macro work there, but a lot of macro, too.
I'm sure you could look for photos in the style you like somewhere in those many pages.
Flickr: The smc PENTAX D FA MACRO 100mm F2.8 WR Pool
In order to understand your needs better, can you expand on why you want such a recommendation? Pentax-specific issues are related to the cameras and lenses, and how they operate, what they are good at and not so good at. This you can learn from any knowledgeable Pentaxian, even if they aren't the best photographers. For example, I am an engineer by trade, so I understand the optical and mechanical properties of camera gear very well, but I'm not a great photographer. I enjoy it, and get some good images, but I'm certainly not great.
In terms of learning the art of photography, that can be done from any great photographer, regardless of the equipment they have chosen.
If you are trying to find out if you can be a great photographer with Pentax gear, the answer is yes. You can likewise be successful with any brand; they all are good. You pick the camera brand based on the features that are important to you, including lens availability in whatever platform you want.