One of my best sellers are the so-called American Flattop style pens (I think they are also called "Parker" style pens, since old Parker pens looked like them). Both Berea and CSUSA have them. I personally like them very much for myself. I do not care for the Cigar style at all, I think they are too big and too heavy. The American style pen is a bit thicker than a standard slimline, and smaller than an European style pen (Montblanc style).
Another option would be the Perfect Fit Convertible pen, from Berea, a very light pen for its size, this is my favourite ball point. It has an excellent Schmidt mechanism, and has for me and others an added benefit: it can be converted in seconds into a pencil, hence the name. So, no need to have both type of kits, pen and pencils, around. I sold only a few pencils last year, and all but two were PFCP, I need only to buy a few pencil inserts and I am prepared.
BTW, both styles take Parker style refills, either ball point or gel.