The best collection and review of sliding lockable knots I am aware of, by :
Joris Hage and Lydia P. E. van der Steen
Locking, Jamming, and Ratchet Mechanisms of Sliding Surgical Knots Topologically Revisited
http://link.springer.com/article/10.1007/s00268-008-9904-2/fulltext.html In this article, the interested knot tyer can find references of the original papers where those knots were presented for the first time. Reading one of those articles, I suddenly realized that the Weston knot is identical to the ABoK#1991 "Jam Hitch" - just as the Dundee knot is identical to the ABoK#1987, and the capsized Tennessee slider is identical to ABoK#1060.
This made me think that it would be very interesting to start by already known bowline-like (PET) loops, and, by reverse engineering

, investigate the possibility that they will be generated by the capsizing of some sliding lockable knot. This may sound a little complicated, but, in fact, it is quite simple :
Take a bowline-like (PET) end-of-line loop.
Pull its bights, and feed the knot s nub with as much rope length as needed, to get a
very loose form of the original loop. You will probably have to consume
much more than the original rope length, so you should better start from a loop with a
very long tail and a
very large eye.
Pull the tail and the eye-leg-of-the-bight of this loop, to the point the segment of the rope between them is completely straightened - it is turned into an unknotted straight line. The original knot would now be transformed into a "reversed" knot.
( Of course, this is possible only in those cases where the
collar structure of the original bowline-like loop is also topologically equivalent to the unknot, just as its
nipping loop structure. Otherwise, in loops where the collar structure is topologically equivalent to the overhand knot, the fig.8 knot, etc, you will not be able to straighten the segment by which it is formed completely... By pulling the tail and the eye-leg-of-the-bight, you will only tighten an overhand knot, a fig.8 knot, etc, but you will not be able to arrive at a straight unknotted line ).
Now, pull the standing end and the eye-leg-of-the-standing-part of this "reversed" knot.
If you are lucky, you may arrive back at the original loop.
We can not know in advance if a bowline-like loop would be "reversible" - or not : i.e., we can not know if its "reversed" knot would be such that, when we will pull the original standing end and the original eye-leg-of-the-standing-end, we will get the original knot - or we will get another knot, topologically equivalent, but geometrically distinct from the original. Topology does not determine geometry ! (*) Every knot has a "reversed" form, but very few are "reversible"- because, most of the time, the "reversed" loose form, when tightened and compactified, will settle to a knot very different from the original.
One would probably think that the complexity of the knots would be the decisive factor : It would be more likely that the most simple knots would be reversible, and the more complex ones would not. Nooope ! Very simple knots, when loosened, will not return to their original form, while more complex ones will. The interested knot tyer should try this "reverse engineering" on the four variations of the "Eskimo bowline" (2), and see what happens...
So, I tried my hand on one of the simpler - if not the simplest - bowline-like loops, the Sheet bend "bowline" - which. although it "looks" like a bowline, and it is PET, is not a "proper" bowline : because it has neither the bowline s "proper" nipping loop, nor the bowline s "proper" collar. ( In fact, it is a loop knot made by interlocked half hitches (1)(2)(3).
Beginner s luck !

See , at the attached pictures, the loose form of the sliding noose-hitch which, when capsized, locks in the form of the Sheet bend bowline-like loop.
1.
http://igkt.net/sm/index.php?topic=3233.msg23702#msg237022.
http://igkt.net/sm/index.php?topic=3233.msg23797#msg237973
http://igkt.net/sm/index.php?topic=3233.msg23712#msg23712P.S. 2012-12-10
As it was pointed out to me by Charles Hamel ( Nautile ), this is not an accurate statement. Perhaps I should had written
"Topology doen not uniquely determines geometry ", or something like that. He kindly offered to me the following correct sentence :
Topology does determine zero to several allowable *knotted* geometrical conformations, in other words it determines a *set* of materially *possible* geometrical configurations.