Ray Skaines mentioned Carl Rohrs using a Pentel Color Pen in a post below. I used to like to use them, but at one point they had been discontinued. I looked all over for them, including the possibility a few refills might show up on eBay. I pulled these out of one of my cabinets. They are probably from about 1984 or so. Almost antiques! The top 1/3 is the pen tip assembly, while the back 2/3 is the sqeezeable ink reservor. The have an interesting "spring" or "snap" in the nylon brush tips. You can drag the tips or even push it. Great for expressive lettering. I don't think they work well for smooth "spencerian" scripts, but maybe that is a result of operator skills and not the technology.
I just did a Google search. Sure enough, they are available again:
http://www.johnnealbooks.com/cgi-local/ ... ?E+scstore
This seems to indicate I was originally correct. They had been discontinued:
Pentel Color Brush
FP57-___. Much sought after, they are available again! Synthetic brush hair springs back after each use. This versatile tool allows strokes from nearly 1/2" to a tiny hairline. For brush lettering. Specify color:
The little pic below looks like Carl's work:
Even if it is someone else's work, you can get the idea.
The sign above was actually painted by Carl Rohrs at a Letterhead meeting somewhere along the way. I managed to snag it from him. He used a Pentel Color Brush to do the original script on a piece of paper. That image was projected and hand lettered on a Turps Marble background.
Also, I noticed they now sell metallic colored inks.
Mike