Another concern, though I am not sure whether this applies to Uros and beardies specifically, is that though they are both healthy and parasite free, they could still potentially infect each other. The natural gut flora in one species, the little organisms that help things break down and digest food, may actually be detrimental to the health of other species. Likewise, illness, bacteria, and viruses that are dormant in one species, can be devastatingly serious in others.
These are the sorts of things people rarely think about when looking at housing different species together in smaller habitats (compared to the big wide world, 4x2x2 is a great size for most Uros!).
Also, the point regarding their diets is also very valid. Unless you are prepared to feed them certain things by hand, daily, I cannot really see a solution to that. Animal protein is required by the beardies, and can be problematic with the Uros.
Now, with this said, there are people who keep specifically Uros and Beardies together, there have been a couple of debates on this forum about it even. Personally, I think these herpers are taking a very large, unnecessary risk, and cannot support the practice. However, this is yet another thing that each keeper has to decide for him/her self.
Out of curiosity, if space is not the issue, why would you like to keep them together? Uros are not social, are beardies?
Good Luck with your decision, let us know what you decide!
Elizabeth

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1.0 Uro Archimedes
0.0 Fish
0.1 Sulcata Minnie
1.1 Iguanas Flik and Loki
0.1 Newfoundland Jasmine
0.1 Feline Winter
Indiana & Wisconsin