Archer was able to create and launch several swords at once but I think it was more a "one sword per Circuit" deal.
Tough while he could theoretically do it, I doubt Shirou would be able to perform 27 tasks at once by simple virtue of not being able to multi-task at such a level.
Also, Shirou only has about 40 to 50 unit of Od, so useless he is contracted to Rin he can't use his Circuits full capacity without killing himself.
Now, if he ever managed to learn how to process Mana into Prana, which is how magecraft is normally performed, that would be something else entirely.
Tough while he could theoretically do it, I doubt Shirou would be able to perform 27 tasks at once by simple virtue of not being able to multi-task at such a level.
Also, Shirou only has about 40 to 50 unit of Od, so useless he is contracted to Rin he can't use his Circuits full capacity without killing himself.
Now, if he ever managed to learn how to process Mana into Prana, which is how magecraft is normally performed, that would be something else entirely.