This is not as easy as it sounds, because bows tend to vary in the angle of the limbs to the riser, and riser length, so a bowyer who knows from experience how to make 44# limbs for his own riser would probably have to experiment to make 44# limbs on your riser unless it happens to have the same length and limb angle as his own risers. This might result in having to make multiple sets of limbs before one hits close to the right weight. Bowyers typically absorb the cost of the occasional missed weight in making their own bows, since the limbs that don't make weight might be used in another bow down the line, but would be less willing to do that for a one of a kind job.
However, call and ask our sponsor bowyers. It is possible that one might make bows that have risers close enough to yours that he would be willing to do the job. Of course, you would have to give up your riser while all this was going on.
Frankly, my own experience with multiple limbs is that either I end up not using one set of limbs at all, or I want to use both sets of limbs so often that I end up ordering another riser.