Thank you SS369,
After your last post, I realized that I had NOT tied this bend till now, and I tried to follow your instructions.
I came up with
three 
, slightly different, re-tucked true lovers bends, and I wonder which is the one you describe, if it is any at all ! LOL
1. You tie a tightened single true lovers bend.
2. You pull the (initial) colars to make some room, alongside the central axis, for the re-tucking of two tails.
3. You pass the two tails ( that are now your working ends)
around the standing ends, to form two (new) colars. Otherwise the tails would slip, and disappear, into the knot, if they would be pulled by the their free ends.
4. Then, you pass the two working ends through the central opening of the loosened knot s nub, in opposite orientations, parallel to the central axis.
5. You end up with a re-tucked true lovers bend, where the tails and the standing ends of each of the two ropes are adjacent, parallel, and coming out of the knot from the same side.
When one has completed the collar forming stage, he has three options in the way he can pass the working ends through the central opening. The working ends can go through the knots nub in a crossing or in two non-crossings ways. I have labeled these two re-tcking ways the S(x) ( x: crossing of the tails just before they exit the knot s nub) and the S(1) and S(2). The crossed tails way produces a slightly larger, in volume, knot, as expected.
Although these knots are somehow symmetric, they are not as much symmetric as the original bend. In the S(1) and S(2) case, we have two symmetric to each other links, but in the S(x) we have the aditional complication of the two tails crossing each other from oposite sides.
I had previously tied many different re-tucked nots, starting from the same true lovers knot, but my philosophy was different. I any place within the knot I saw a pair of two adjacent rope strands, I tried to "feed" it by a third strand going adjacent to the original two. I had tried to find a path inside, or around, the knot s nub, so the re-tucked tails pass by this place. My initial purpose was to have nipping loops going around three rope diameters, in the spirit of my original question about bends suitable for stif ropes. So, I have been tying very different knots, and I overlooked those three you have suggested.
P.S. 2011-1-22 : I have completely mis-understood the simple set of re-tucking rules offered to me by SS369, so I have tied completely different knots ! Read the following posts, where I was finally able to understand what has been told to me right from the begining...
http://igkt.net/sm/index.php?topic=1919.msg16373#msg16373 
