What limits the number of skylights you can put in a room?
There is no structural reason why you cannot put skylights between each truss.

As long as you don't interfere with the trusses themselves, all you're doing is replacing the weight of the roof and shingles for the weight of the skylights.

You may, however, find that the skylights themselves make the idea difficult, as they are likely to have fairly wide flanges on either side to help avoid water penetration.  Those flanges are likely to get in each others way for a side-by-side install.

However, in a side-by-side install, you could cut them down and set one on top of the other, just be sure to very fully seal the entire seam where the flanges are cut.