The two SLR lenses you have should cover the portrait work.
A focal length of 50mm is about what you need.
The Pentax lens should do well for portraits.
The Canon lens is fine when you zoom it out to about 3X.
If you want a camera with interchangable lenses you could look at one of the mirrorless DSLR cameras.
They are a bit smaller and lighter.
Here is a comparison:
A point and shoot camera can do a good job except for low light situations.
The Canon G15 is a good choice as it has manual controls, an optical viewfinder and an excellent lens.
For a bargain camera with manual controls and a big zoom look at the Panasonic ZS15/TZ25.
It has an exceptional lens for the price.
Don't let the salesman tout you onto the ZS20/TZ30 just because it has more gizmoes and more zoom.
It has too many megapixels and a lens with soft corners (vignette).
Point and Shoot cameras with more than 12 megapixels will suffer from loss of detail.
I would love advice on what camera (or additional lens) I should get. I will be using it for mostly self-portraits (I'm a makeup artist and have a blog, so I want to be able to take close up self-portraits of makeup techniques), photos of makeup products, and travel photography. I currently own a Canon EOS Rebel XT with EFS 18-55mm lens, Pentax K1000 with Pentax-M 1:1.4 50mm lens, and a Sony Cyber-shot DSC W120 7.2 megapixel point and shoot. I love shooting travel photos with my Pentax, but it's so heavy and film is kind of a pain. I would love to find something that is digital, a little lighter than my Canon and Pentax, but not as small as my Cyber-shot, and that I can also use for sharp self-portraits and product photos. Does this kind of camera even exist?! Or would it be best to get a nicer point and shoot for travel photos, and a better lens for portrait/product photos? I so appreciate any suggestions you may have!