RICHARD - Obviously there are all kinds of shapes and sizes of all of gods children for example, Dwarfs, obese, tall, skinny etc. Will there be an opportunity for us to change our shapes and sizes during the mellenium or when we are resurrected?

JOEL - The scriptures say:

"The spirit and the body shall be reunited again in its perfect form; both limb and joint shall be restored to its proper frame, even as we now are at this time; and even there shall not so much as a hair of their heads be lost; but every thing shall be restored to its perfect frame, as it is now,"(Alma 11:41-)

The resurrection process will eventually cause our bodies to return to a condition resembling the prime of our life, without disease or imperfections. According to some church leaders this change could happen immediately or over the course of time according to the providence of God. I know of no scriptures or doctrines that suggest that we will have any control of what our bodies will look like after the resurrection.
Children will rise as they were laid away, but after the resurrection their bodies will grow to the full stature of their spirits.
Joseph Smith said, pointing to the mother of a lifeless child, “You will have the joy, the pleasure, and satisfaction of nurturing this child, after its resurrection, until it reaches the full stature of its spirit.” (Gospel Doctrine, 455-56)

According to Joseph Fielding Smith:
"In the resurrection from the dead, the bodies which were laid down natural bodies shall come forth spiritual bodies. That is to say, in mortality the life of the body is in the blood, but the body when raised to immortality shall be quickened by the spirit and not the blood. Hence, it becomes spiritual, but it will be composed of flesh and bones, just as the body of Jesus was, who is the prototype. Bodies will come up, of course, as they were laid down, but will be restored to their proper, perfect frame immediately. Old people will not look old when they come forth from the grave. Scars will be removed. No one will be bent or wrinkled. How foolish it would be for a man to come forth in the resurrection who had lost a leg and have to wait for it to grow again. Each body will come forth with its perfect frame. If there has been some deformity or physical impairment in this life, it will be removed."

He also said that the resurrected person will "be the same person we knew... in our mortal existence, even to the wounds in the flesh. Not that a person will always be marred by scars, wounds, deformities, defects, or infirmities, for these will be removed in their course, in the proper time. Defects will be eliminated and men and women shall attain to that perfection of their spirits, to the perfection that God designed in the beginning." (Doctrines of Salvation, 1954-1956)

I am not sure how far reaching this concept of having a "perfect frame" is or what would be included in "deformity or physical impairment". I only know that when we are resurrected we will obtain a form comparable to what our spirits look like and that we will be recognized by those who know us. So I guess if in the prime of our life we naturally had a short stature or tall stature we will still look that way when resurrected. But if for example our obesity(or any other deformity) was caused by some disease or defect in our metabalism or DNA, that will be corrected at resurrection and we will no longer have that deformity.
Joseph Fielding Smith also said:
"The question has frequently been asked when a child has been born with some physical defect or deformity, was this a punishment or a condition which was his before he was born? No! All of these ills are ills of the flesh or defects that are due to mortal conditions which may have come upon the body even before birth, but we may be assured that these defects were not conditions which existed in the world of spirits." (Answers to Gospel Questions, vol. 4, p. 185)

Our bodies will also look different depending on which level of heaven we are to abide in after the judgment. In the book, "Doctrines of Salvation" we read:

"In every species of animals and plants, there are many resemblances in the general outlines and many specific differences characterizing the individuals of each species. So in the resurrection. There will be several classes of resurrected bodies; some celestial, some terrestrial, some telestial, and some sons of perdition. Each of these classes will differ from the others by prominent and marked distinctions; yet, in each, considered by itself, there will be found many resemblances as well as distinctions. There will be some physical peculiarity by which each individual in every class can be identified." (Doctrines of Salvation Vol. 2, p. 287)

The fact is we only worry about things like our size and shape in our mortal existance. In the next life there will be no more vanity, ego, or pride so noone will really care what they look like and won't want to change their appearance. I think God will be in control of what our bodies finally look like. The most important thing is to be resurrected with a body so we can become like our Father in heaven and obtain exaltation.