@drifand and @Ethan_PT7 : the recessed “clip” in all these designs is certainly an interesting variation on the theme, and has the clear advantage of removing the very source of the “problem” from the outset; some executions may be better thought or crafted than others, but it is for sure a solution nonetheless.
Unfortunately, at least from my perspective, these different form factor scan sometimes introduce a cure which turns out to be worse than the ailment itself. To begin with, the integrated clips like the one in a Dyson Biro (or specimens alike) introduce a discontinuity in the barrel structure which I find very “unnatural”, and certainly unappealing: I have always seen the pencil or the pen as a materialisation of our fingers, or of a scalpel, or of our own thoughts, and I cannot imagine either of those concepts as being “hollow” in any way, shape or form.
Setting aside for a moment the issues of mechanical balance introduced in the process of milling or caving part of the rear barrel, and ignoring the possible torsions of the fabric in a pocket induced by the placement (even deeper than usual) of the clipping negative space, the “hook” created by the clip being part of the body introduces in and of itself the same sensation of unevenness and “scratchy-ness” a standard clip would make me feel while I write or sketch. We are basically trading a set of problems for a vaguely different set of problems, or rather a similar set of problems with a wholse new set of constraints.
The additional hassle in this scenario is that, while a traditional clip can be (in most cases) simply slid off of a barrel, in the case of a Dyson Biro one ought to physically reconstruct the barrel in order to restore a perfectly cylindrical or tapered body. Which is, obviously, madness.
I reckon that the integrated clip can be for sure someone’s cup of tea — I myself bought a stylus for a tablet screen with that design a few years ago: not bad at all, considering I seldom used it — but when it comes to strict preferences I still choose the naked and whole power of an un-modified barrel, possibly cylindrical and with a removable clip.
I appreciate, however, the amount of ingenuity and creativity stemming from such a design principle, and I find some bolt-action artisanal pieces really well made. 
